Leonardo's handwritingLeonardo usually wrote with his left hand, filling the page from the right margin inward. When viewed with a mirror, his handwriting takes on what is, for us, a "normal" appearance. His calligraphy changed over the years, from the elegant, ornate forms of his youth to the neat, even-spaced lettering of his maturity. In his last years, his writing became irregular, abbreviated, and at times sloppy.
Some of Leonardo's manuscripts survive in their original form; others, like the Codex Arundel and Codex Atlanticus, were compiled after his death from the original notebooks broken up by collectors to form collections on particular topics.
Of the original manuscripts, some, like Manuscript D, are ordinary notebooks filled in a reasonably ordered sequence; others, like Codex Forster III, are pocket notebooks filled with jottings and drawings in random order.
Arrangement of the manuscripts
Leonardo nearly always began his manuscripts from what we regard as the last page. Often, as in the Leicester Codex, he wrote on loose sheets, binding them together in book form only when complete. At times, as in the Codex on the Flight of Birds, he used a gathering for botanical and anatomical drawings, then, after a brief interval, overwrote the same pages with various annotations.
Rarely does a leaf or manuscript volume of Leonardo constitute an orderly, coherent text. The one exception is Madrid Manuscript I, which, in places, reveals an attempt to compile a well-organized treatise on mechanics.