Various subjects are covered in this manuscript including painting, perspective, water and mechanics.

Theories regarding painting expounded here provide the basis for much of the Codex Urbinas and consequently the treatise on painting. Leonardo’s recommendations to the painter regarding the execution of the perfect portrait are of particular interest.

Although dated 1492, the notes may have been begun earlier, around 1490. Manuscript A is a fragment of a manuscript which comprised originally of 64 folios including the Codex Ashburnham II.