Sir Martin Conway continues:
In these volumes Dürer is seen, sometimes writing under the influence of impetuous impulse, sometimes with leisurely care, allowing his pen to embroider the script with graceful marginal flourishes.
At what period of his career Dürer first conceived the idea of writing a comprehensive work upon the theory and practice of art is unknown. It was certainly before the year 1512. The following list of chapters may perhaps be an early sketch of the plan.
Ten things are contained in the little book.
The first, the proportions of a young child.
The second, proportions of a grown man.
The third, proportions of a woman.
The fourth, proportions of a horse.
The fifth, something about architecture.
The sixth, about an apparatus through which it can be shown that 'all things may be traced.