Quantum Theory and the Schism in Physics is one of the three volumes of Karl Popper's Postscript to the Logic of scientific Discovery. The Postscript is the culmination of Popper's work in the philosophy of physics and a new famous attack on subjectivist approaches to philosophy of science. 'What distinguishes Popper from a great dull army of philosophers of science is that reading him is good for us' Donald MacKay in Nature