this is the first translation into english of the seminal work by one of the earliest exponents of cartesianism in france and a leading contributor to the theory of causality which came to be known as occasionalism. la forge also provides a sophisticated version of cartesian mind-body dualism. this edition, which includes an introductory essay on la forges philosophy and comprehensive editorial notes, provides an ideal introduction for students of early modern philosophy to many of the issues which were subsequently developed by malebranche and expressed in their definitive form in david humes analysis of causal relations. this text complements recent new translations into english of malebranches works and is suitable for graduate courses and upper-level courses in early modern philosophy.