Berkeley is popular in the philosophical tradition as the philosopher who denied the existence of matter in favour of spiritual substance. His esse est percipi thesis is understandably seen as a recipe for subjective idealism. While there is a point to this reading of Berkeley, it remains to be seen whether it does justice to the full significance of Berkeley's opposition to philosophical materialism. In this book, essentially a sympathetic reconstruction of Berkeley's philosophy, Ilodigwe approaches Berkeley's Immaterialism from the standpoint of the philosophical issues raised by the emergence of modern science in the seventeenth century. He argues that when approached in this manner, Berkeley's opposition to philosophical materialism not only emerges as an attempt to overcome false abstractions, but it also becomes possible to make sense of his claimed alliance with common sense in his battle against philosophical materialism. While the realist portrait of Berkeley that emerges from this exercise is not free from difficulties, it arguably offers us a fuller conspectus of Berkeley's philosophy of immaterialism.