Bird Song has long been an inspiration to poets, and a delight to many other people, but why do birds sing? Bird song has been studied extensively in the past few decades, so that there is now hardly an area of animal behaviour on to which studies of song do not shed light. This book explores the study of bird song from the biological viewpoint, reviewing the literature written on the subject and considering its intricate nature. It is written with a wide readership in mind so that, while undergraduate and postgraduate students of biology may gain particularly from it, both professional biologists interested in bird behaviour and amateur ornithologists with some knowledge of biology will also find it a mine of information.