Originally published in 1951, this concise book presents an engaging study of the works and influence of the renowned English philosopher Ralph Cudworth (1617–88), the leader of the Cambridge Platonists. A bibliography of writings by and about Cudworth is also included, together with an appendix section on his manuscripts. The text was an early work by Australian philosopher and historian of ideas John Passmore (1914–2004). This book will be of value to anyone with an interest in Cudworth, the Cambridge Platonists and the historical development of philosophy.