Bonaventura Cavalieri (1598-1647), one of the most important mathematicians of his period, was professor of mathematics at Bologna from 1629 until his death. 'He is mainly remembered for his use of the principle of indivisibles, formulated by him in 1629, but not published until it appeared in his Geometriae indivisibilibus continuorum, 1635. This was expanded in his Exercitationes geometricae, 1647, and reisssued with corrections in 1653' (Thornton). This is a fine copy, without the usual Manhattan library stamps, of the very rare first edition (not in the Honeyman collection which has only the second edition of 1653).