Omni is unusual among the small plates books for having no single author. The text passes through five successive keepers of the record, Omni, his son Amaron, Amaron's brother Chemish, Chemish's son Abinadom and Abinadom's son Amaleki, each adding only a short passage before handing the plates on, so that the book reads as a chain of brief notices rather than one person's composition. Most of these contributions amount to little more than a statement of who is writing, what has happened in general terms, usually further conflict with the Lamanites, and to whom the plates are being passed next.
The final and longest contribution belongs to Amaleki, who breaks from the pattern of terse handoffs to narrate a genuinely significant event: with no heir to leave the plates to, he gives an extended account of his own life and of the discovery, in his generation, of a people called the people of Zarahemla, setting up the material that follows in the book of Mosiah.
Omni's chain of brief keepers each note continuing warfare with the Lamanites and, in several cases, open acknowledgment of their own wickedness or spiritual weakness, a note of self-criticism from within the record that recurs across the Book of Mormon whenever a keeper reflects on the state of his own people rather than simply reporting events.