Question 15
Does the Book of Commandments Contain all Revelations?

Why aren't there any references in the Book of Commandments concerning the First Vision, the identity of Moroni, the restoration of the priesthood, the identity of Peter, James and John, or of John the Baptist?

Response by Stan Barker and Malin Jacobs

Why should the Book of Commandments necessarily contain references to the people or events listed above?  The book is, after all, a Book of Commandments containing selections from the revelations received up to the time of its publishing.  It does not pretend to contain everything the Prophet Joseph learned or experienced up to that time.

Bruce R. McConkie defined the Doctrine & Covenants as

That volume of latter-day scripture which contains selections from the revelations given to Joseph Smith and his successors in the Presidency of the Church. . .  .  Certain parts of these revelations were published in Independence, Missouri, in 1833 under the title Book of Commandments, but mob violence destroyed the printing press and stopped the work at that time.  By 1835, however, a new and enlarged selection of revelations had been made by the Prophet, and the first edition of the Doctrine and Covenants came off the press.

                                                                                    Mormon Doctrine, p. 205

Earliest known discussion:

This one.