Mormon fulfills his promise to Ammaron and retrieves the Nephite records. He does not tell us what he retrieved, but it is useful to examine the scope of the records to which Mormon had access. Our best clue as to the extent of the records comes when Mormon is describing the small plates of Nephi:
Words of Mormon 1:3
3 And now, I speak somewhat concerning that which I have written; for after I had made an abridgment from the plates of Nephi, down to the reign of this king Benjamin, of whom Amaleki spake, I searched among the records which had been delivered into my hands, and I found these plates, which contained this small account of the prophets, from Jacob down to the reign of this king Benjamin, and also many of the words of Nephi.
There were sufficient records in the collection of plates that the set comprising the small plates of Nephi were not obvious. They were found only after searching. This suggests that there were large numbers of plates. It also suggests that the records were not bound into a single entity, but were rather bound multiply. It is most probable that each of the books that is given a separate name was bound as a separate unit. There are two reasons for this supposition. The first is that there had to be multiple bound sets, or else the single bound set of the small plates of Nephi could not have been unobvious in the collection. The second reason for the supposition is simply a matter of size and convenience. Had there been a single record of all of the records, it would become unmanageably large and heavy. Therefore we are safe in assuming multiple sets of records, each bound in similar ways. This assumption again follows for the “invisibility” of the small plates of Nephi. They did not stand out in form against the other records.
The materials to which Mormon had access therefore probably looked something like this:
The book of Nephi (the elder) is a special case because Mormon tells us that it is a shorter version than the one on the official plates of Nephi. Therefore, we learn that individual prophets might make records. Combined with the certainty of the unstated record of Ammon and Aaron, we may readily expect that there were many shorter accounts from different people. It would be these shorter accounts that increased the volume of source material Mormon had available to him. However, it is also improbable that these shorter records of individuals were on gold plates, as that is a technology that appears to have required state resources, if the ending of the book of Omni is an indication (see the commentary following Omni 1:30 as well as the Provenance of Mormons sources at the beginning of 1 Nephi).
After retrieving the plates, Mormon sets about his task. That original task was to be the same type of scribe that Ammaron had been. Mormon wrote in the plates of Nephi. What he wrote there is not this current book of Mormon. He makes this clear when he indicates:
“And behold I had gone according to the word of Ammaron, and taken the plates of Nephi, and did make a record according to the words of Ammaron. And upon the plates of Nephi I did make a full account of all the wickedness and abominations; but upon these plates I did forbear to make a full account of their wickedness and abominations…”
Mormon contrasts the full account on the plates of Nephi with the abbreviated account on “these plates.” “These plates” are those of his abridgment, the record we know as the Book of Mormon. Mormon therefore wrote history once, and then at some later point writes history again, but for a different audience. His first writing would certainly be for the same contemporary audience as the rest of the plates. “These plates” have an audience in the future.