He wrote a book called Eternal Lives, which deals with the principle of multiple lives… Here is Chapter two from that book :-)

About the 2,555,000,000 number, please see this comment.

I’d be interested in any alternative sources of the above that also site Joseph.

The Answer., Times and Seasons, vol. 5 (January 1844-January 1, 1845), No. 24. Nauvoo, Illinois, Jan. 1, 1845. Whole No. 108, p.758
Well, now, Brother William, when the house of Israel begin to come into the glorious mysteries of the kingdom, and find that Jesus Christ, whose goings forth, as the prophets said, have been from of old, from eternity; and that eternity, agreeably to the records found in the catacombs of Egypt, has been going on in this system, (not this world) almost two thousand five hundred and fifty five millions of years: and to know at the same time, that deists, geologists and others are trying to prove that matter must have existed hundreds of thousands of years;-it almost tempts the flesh to fly to God, or muster faith like Enoch to be translated and see and know as we are seen and known!

(Was this from his translation of one of the facsimiles?) He said “an eternity” equals 2.555 billion years. That is very interesting in light of the “one day is with the Lord as a thousand years, and a thousand years as one day” (2 Peter 3:8; Abr. 3:4). So a year to the Lord would be 365,000 years to us (assuming linear). 2.555B divided by 365K is an even 7000. 7000 years to Him is an eternity to us. The 7000 years is interesting in light of D&C 77 and the earth’s “temporal existence”.

Anyway, if someone had to spend 2.555 billion years (an eternity) in the kingdom/degree-of-glory for which they qualify after this (or each) mortal probation, that would be a huge incentive not to squander this precious opportunity! If true, maybe they spend that time preparing to progress.

However, the term “worlds without end” is also interesting. It could also be that this single mortal probation is totally effective at sifting eternal potential and limits (quality of spirit), i.e. determining who can handle exaltation and who can’t (and never will be able to).

I think we learn from D&C 19:6-12 that we need to be careful how hard we interpret scriptural superlative words (like forever, never, alway, endless, eternal, etc.).

Today many Church members are unaware that these pre Christian teachings were ever taught in the Church as a viable doctrine. The doctrine was no longer taught publicly after about 1898 when Apostle and Counselor in the First Presidency, George Q. Cannon, gave a talk before the first Sunday School conference entitled “Things which Should not be Taught in Sunday School.” In this talk Cannon says he thinks it “not wise” to advocate the Adam God Doctrine, Multiple Mortal Probations,or Plural marriages.
Others disagreed, Apostle Orson F. Whitney, for example, in a 1919 article in the church publication Improvement Era, “subtly expressed his disappointment” that multiple probations weren’t taught as church doctrine.
A major reason for opposition .University of Utah historian Gae Lyn Henderson observed in her response to A recent lecture on the subject ”What we might label ‘second chance theology’ takes the fear out of religion, and that fear-free religion loses its power to strictly control human behavior” The teachings were dropped for various reasons — Many feel it was to a large extent, because the church was taking so much criticism from the secular world for doctrines they were unable to understand. Another view is that the concept of Mortal Probations represents a threat to the very essence of Orthodox Christianity; The early Hebrews believed that “without the shedding of blood there could be no remission of sin.” (Heb. 9:22) They accepted the primitive idea that God could not be appeased except through blood sacrifice, .therefore there was a need for Christ’s redemptive sacrifice , The Orthodox never understood that the sacrifice had to be the animal within and not some poor helpless creature without. Crucify the evil within “The Crucifix is the emblem and symbol of the Son of God, not because Jesus shed his blood upon the cross for the sins of man, but because the Christ is crucified perpetually so long as sin remains.” ~The Book of Illuminations
. St. Francis of Assisi And all the creatures, which are under heaven, each according to its nature, serve, know and obey their Creator better than you. • And even the demons did not crucify Him, but you together with them have crucified Him and even now you crucify (Him) by delighting in vices and sins. ~
If we are to pay for the consequences of our sins ourselves in further lives and attain salvation through our own efforts, the sacrifice of Christ becomes pointless
I agree with George Cannon.Discover the truth and then don’t speak unless you can improve the silence I have discovered many privately accept it which publically denounce it.Many who are unfamiliar but have heard of this concept like to refer to the Mattias incident. About 1835 Joseph Smith was visited by a man, named “Joshua the Minister”. “Joshua’s” real name was Joseph Matthias. He claimed that he a descendant of the Apostle Matthias, and that the soul passed from father to son. Joseph Smith said that Matthias’ “doctrine was of the devil” and that he was a murderer (DHC 2:304-05)
I first though this was a contradiction, but Joseph Smith was not saying the concept of mortal probations was a doctrine of the devil, but that Matthias himself was a devil, and “his doctrine” (that the soul passes from father to son) was a doctrine of the devil. It should be noted that Joseph Smith never used the term transmigration of the soul or reincarnation.
“Joshua the Minister” (Joseph Matthias) was not teaching mortal probations but a strange doctrine of the transmigration of souls from father to son.
Over a period of almost two millennia, the Christian Church oppressed and brutalized millions of individuals in an attempt to control and contain spirituality.. Today we have kinder, more gentle people who control spirituality and try to explain the mysteries with opinions , assumption dogmas and doctrines. Truth has many doors waiting to open to those who knock. There is a teaching that is right for everyone according to their level of learning, or enlightenment, but as Jesus once said from the Gospel of Thomas” for he who seeks, let him find bread and not stone”.
When the Eagles are silent, The Parrots began to jabber
Michael Otter son, Director of LDS Church affairs, recently said he thought the LDS church was closest to the Unification church in Philosophy. Members of this church are called ‘Moonies’
As man is, God once was; as God is, man may become.”
A Mormon Church leader in denial:, ” Now that’s more of a couplet than anything else. That gets into some pretty deep theology that we don’t know very much about
I don’t know that we teach it. I don’t know that we emphasize it. I haven’t heard it discussed for a long time in public discourse. I don’t know all the circumstances under which that statement was made. I understand the philosophical background behind it. But I don’t know a lot about it and I don’t know that others know a lot about it. [Emphasis added]
The soul comes from God and is destined to become as God.” These beliefs became known as the lost doctrines of Christianity. Ancient teachings that were restored by Joseph Smith. We may attempt to cut ourselves off from the philosophy of the ancients, but since they are based on true principles, we shall be forced to return. A river cannot separate itself from its source and we cannot separate ourselves from the teachings of Joseph Smith. There is no harm for the current leaders to distance itself from early church teaching,but due to the abundance of contradictory evidence, to deny is impossible
Galileo said:”The authority of a thousand is not worth the humble reasoning of a single individual.”
Another well respected Church leader Bruce McConkie attacked the theology of the early church and Joseph Smith more directly, ridiculing the idea of plural probations. “There is no such thing as a second chance to gain salvation,” he said in a 1980 church address titled “The Seven Deadly heresies”
. I entertained Bruce McConkie’s view briefly and discovered his teachings were opinions on top of assumption and flavored with dogmas McConkie’s thoughts are entertaining to those who want to be taught that God had sex with Mary to produce Jesus, or that Jesus and Satin are brothers. Many seek answers and not opinions and assumptions. The ancients taught that truth can be found in the unity of though among enlightened thinkers then it is obvious that McConkie is not Plato and Otterson certainly is no Socrates. We should listen to everyone, Always keep an open mind and let the winds of facts and evidence blow you about as though you were a leaf, with no direction of your own. . Surrender to the truth as quickly as you can.
Mormon Apostle Hugh Brown said: And while all members should respect, support, and heed the teachings of the authorities of the church, no one should accept a statement and base his or her testimony upon it, no matter who makes it, until he or she has, under mature examination, found it to be true and worthwhile; then one’s logical deductions may be confirmed by the spirit of revelation to his or her spirit, because real conversion must come from within… Speech at BYU, March 29, 1958
“Let every man judge according to his own standards, by what he has himself read, not by what others tell him”. Albert Einstein
Many members of organized religion are social annimals, only with the herd is he happy. He cares little if the teachings are truth, superstitions or dogmas as long as it is the view of the herd. He does not think for himself, but lets others do it for him if any unusual doctrine is presented to the typical member he will reply “If that is true why hasn’t the prophet or Pope told us?”

I actually have no objections to a member of the church believing there is no progression between kingdoms (see my post that says just that here). I did object to the opening statement in your comment though: “Why don’t we all just stick to the teachings of the scriptures and of the prophets, instead of relying on our own philosophies on this issue?”. As you can see, I am sticking with the words of prophets when I say there is the possibility of progression between kingdoms. It is unwise and uncharitable to imply that those who disagree with your personal opinion are rejecting prophets in favor of their own philosophies. That accusation could go both ways in these cases and is utterly unhelpful.

Now about the rib. As for the Lord taking a rib out of Adam’s side to make a woman of, he took one out of my side just as much.
“But,” brother Brigham, “would you make it appear that Moses did not tell the truth?”
No, not a particle more than I would that your mother did not tell the truth, when she told you that little Billy came from a hollow toad stool. I would not accuse your mother of lying, any more (p. 15) than I would Moses; the people in the days of Moses wanted to know things that were not for them, the same as your children do, when they want to know where their little brother came from, and he answered them according to their folly, the same as you did your children.
…
I tell you more, Adam is the Father of our spirits. He lived upon an earth; he did abide his creation, and did honor his calling and priesthood, and obeyed his master or Lord, and probably many of his wives did the same, and they lived, and died upon an earth, and then were resurrected again to immortality and eternal life.
“Did he resurrect himself?” you inquire. I want to throw out a few hints upon the resurrection as it seems to come within the circuit of my ideas whether it ought to come within the circuit of my remarks or not. I believe we have already acknowledged the truth established that no person can officiate in any office he has not been subject to himself and been legally appointed to fill. That no person in this kingdom can officiate in any ordinance he himself has not obeyed; consequently no being who has not been resurrected possesses the keys of the power or resurrection. That you have been told often. Adam therefore was resurrected by someone who had been resurrected.
…
I reckon that Father Adam was a resurrected being, with his wives and posterity, and in the Celestial kingdom they were crowed with glory, immortality, and eternal lives, with thrones, principalities, and powers: and it was said to him it is your right to organize the elements; and to your creations and posterity there shall be no end, but you shall add kingdom to kingdom, and throne to throne; and still behold that vast eternity of unorganized matter. Adam then, was a resurrected being; and I reckon, our spirits and the spirits of all the human family were begotten by Adam, and born of Eve.
“How are we going to know this?” I reckon it.
And I reckon that Adam came into the Garden of Eden, and did actually eat of the fruit that he, himself planted; and I reckon there was a previous understanding, and the whole plan was previously calculated, before the Garden of Eden was made, that he would reduce his posterity to sin, misery, darkness, wickedness, wretchedness, and to the power of the devil, that they might be prepared, for an exaltation, for without this they could not receive one.
…

I tell you, when you see your Father in the heavens, you will see Adam; when you see your Mother that bears your spirit, you will see mother Eve. And when you see yourselves there, you have gained your exaltation; you have honored your calling here on the earth; your body has returned to its mother earth; and somebody has broken the chains of death that bound you, and given you a resurrection.
(Brigham Young, Unpublished Discourse, LDS General Conference, October 8, 1854)

For example BRM wrote in a letter to Eugene England, February 19, 1981:

In that same devotional speech I said: “There are those who believe or say they believe that Adam is our father and our God, that he is the father of our spirits and our bodies, and that he is the one we worship.” I, of course, indicated the utter absurdity of this doctrine and said it was totally false.

Since then I have received violent reactions from Ogden Kraut and other cultists in which they have expounded upon the views of Brigham Young and others of the early Brethren relative to Adam. They have plain and clear quotations saying all of the things about Adam which I say are false. The quotations are in our literature and form the basis of a worship system followed by many of the cultists who have been excommunicated from the Church. I also received, of course, your material in which you quote from Brigham Young and others of the early Brethren saying that God is progressing in knowledge.
…
Yes, President Young did teach that Adam was the father of our spirits, and all the related things that the cultists ascribe to him. This, however, is not true. He expressed views that are out of harmony with the gospel.

http://magazine.mormonfundamentalism.org/McConkie_England.htm

BRM goes on to claim that Brigham Young also believed the opposite view, that Adam was not the father of our spirits, essentially accusing him of revelatory or theological schizophrenia (in the vulgar sense of the term). He also claims that Brigham Young both did and didn’t believe in the proposition that God was progressing in knowledge.

So essentially BRM’s position is that at best Brigham Young was the worst sort of loose cannon, creating doctrines that are now the basis of apostate cults willy nilly in general conference. That is fine, of course, as long as he is honest about it. Other leaders have generally claimed that Brigham Young was misinterpreted, which is ridiculous.

This October 8, 1854 discourse is the locus classicus for the doctrine:

http://www.xmission.com/~country/by/100854_2.htm

Now I happen to agree that Brigham Young’s A/G doctrine was wrong in certain critical respects, but he definitely taught it. In other respects however, I think Brigham Young understood the truth as taught by Joseph Smith far better than BRM ever did, in this life, in particular in regard to eternal progression, the fall, baptism, the state of the telestial glory, and all the other points that separate classical Mormonism from neo-Hellenistic Mormonism.