Berkeley (1685-1753) held that matter does not exist, and that the sensations we assume are caused by an indifferent and independent world are instead caused directly by God. Nature has no existence apart from the spirits who transmit and receive it. In this book, the author presents these conclusions as natural (though by no means inevitable) consequences of Berkeley's reflections on such topics as representation, abstraction, necessary truth, and cause and effect. The author offers new interpretations of Berkeley's views on unperceived objects, corpuscularian science, and our knowledge of God and other minds.