For a long time, I did not know how to structure this volume. Sometimes, it seemed that the biologists could speak for themselves without the help of philosophers. While there is some truth to this, I soon realised that scientists were calling for philosophy to leave its isolation. It also seemed that I could not make sense of the recent turn in biology except by looking at the philosophical tradition that it rejuvenates, tied to an organic conception of nature, and opposed to the mechanistic understanding upon which modern science is founded. This neglected tradition promulgated a dialectical biology that placed the organism at the centre of evolution. But modern biology abandoned organicism, reified nature and thereby forgot about life. Both these trends are evident in the Modern Synthesis (MS), the tradition I aim to reconstruct in this work. In this introduction, I outline the chapters, provide some of the background for my approach, and indicate the aims of the book.