Aside from biographies, which are plenty and mostly good, there&#x27;s nothing better than being able to go to the source! All of his surviving notes are available in illustrated and annotated forms.<p>I found them once when I was at the uni library... before I knew it hours had passed and I was still cross-legged on the floor going through them.<p>Also &quot;Leonardo&#x27;s Universe&quot; is great to have... full of illustrations and notes about his time.