“Like Unto… the Plates of Brass, Save There Are Not So Many”

Joseph F. McConkie, Robert L. Millet
The brass plates were definitely more extensive in scope than the Old Testament, containing, for example, the oracles of Josephite prophets like Zenos and Zenock (see 3 Nephi 10:16).

Doctrinal Commentary on the Book of Mormon, Vol. 1