This chapter proposes to draw attention to some contributions that Popper has made in the fields of philosophy, logic, and scientific method, the significance of which appears to have been overlooked. It adds a brief description of a contribution which has not been published. Whether one looks at different treatments of modern logic or at textbooks of the subject since they first began to appear about thirty years ago, one is left without any explanation of the goal of the whole subject. The general conception that Popper has put forward has a consequence for traditional logic that is of considerable interest. Returning to the idea of the counter-example, let us enquire into the bearing this has on scientific procedure. According to Popper, an empirical hypothesis is not verifiable but is falsifiable, and this is because falsity is transmitted from the conclusion to at least one of the premises but truth is not.