"Galileo's notes on motion and mechanics document his work on mechanical problems over a period of more than forty years. The manuscript consists of more than 300 pages. They contain numerous short texts in Latin and Italian, representing sketches of proofs, but also extended drafts intended for publication, calculations, tables of calculated numbers, diagrams, and even some documents pertaining to experiments performed by Galileo. The manuscript is considered the essential source of information on the intellectual route followed by Galileo in achieving the insights he submitted in the Discorsi."