The statistical issues in drug development are explained in this book, enabling non-statistians to work more easily alongside their statistical colleagues in planning, analysing and interpreting clinical trials. The author aims to make the book of particularly benefit to the physician who might have little access to statistical expertise. Drug development brings its own commercial pressures whilst regulatory standards determine that much of the work is examined very closely. As a consequence, the non-statistician working in drug development has to possess considerable appreciation of statistical issues, and this book aims to provide that.