This work aims to help students with the mathematics required when tackling investigative assignments during an advanced study of biology, particularly in ecological studies. The book is written round the assumption that mathematics is a tool to explain the results of biological investigation, and emphasis is placed on explaining why the various techniques are used. In particular, guidance is given on when data should be tested, how data should be collected, how to select the appropriate test, how to feed numbers into a "black box" equation, the significance of the answer in biological terms and how to pronounce mathematical symbols. Authentic case studies are used to introduce each technique, and there are examples from investigations in biochemistry, genetics, human and social biology, behaviour and ecology.