The title “Book of Moses” is not the original name for the material from the Joseph Smith Translation of Genesis that appears in our Pearl of Great Price, but it is used as a convenient title. The original edition of the Pearl of Great Price was published in 1851 by Elder Franklin D. Richards of the Quorum of the Twelve Apostles. In that edition, there was no book of Moses as such. Instead, Elder Richards included two distinct extracts from the Joseph Smith Translation.
The first was called “Extracts from the Prophecy of Enoch, containing also a Revelation of the Gospel unto our father Adam, after he was driven out from the Garden of Eden” and contained what is now in Moses 6:43–7:69. The second of the two extracts was entitled “The words of God, which he spake unto Moses at the time when Moses was caught up into an exceeding high mountain, and he saw God face to face, and he talked with him, and the glory of God was upon Moses; therefore Moses could endure His presence.” This extract contained what is now in Moses 1:1–4:19, 22–25; 5:1–16, 19–23, 32–40; and 8:13–30. The entire book of Moses as we think of it today was not present in the original Pearl of Great Price.
When he prepared the 1878 edition of the Pearl of Great Price, Elder Orson Pratt of the Quorum of the Twelve Apostles put the material from the Joseph Smith Translation into the Pearl of Great Price in the form that we have it today. Moses 1 was organized as a separate document called “The Visions of Moses,” while the rest of the material was contained under the heading “The Writings of Moses.” (This is incidentally how the Community of Christ organizes the first chapters of the Joseph Smith Translation to this day.)