The Codex Forster comprises three parchment-bound volumes containing 5 notebooks.

The drawings in these pocket notebooks include studies on mathematics, geometry, weights, and hydraulic machines, carried out at different times between 1490 and 1505.

There is also a well-arranged sequence of theorems dealing with the transformation of geometrical forms such as polygons and polyhedrons of the type Leonardo illustrated for Luca Pacioli’s De Divina Proportione.