This book is designed to be a concrete, digestible introduction to the area that has come to be known as “bioinformatics” or “computational molecular biology”. My own teaching in this area has been directed toward a mixture of graduate and advanced undergraduate students in computer science and graduate students from the biological sciences, including biomathematics, genetics, forestry, and entomology. Although a number of books on this subject have appeared in the recent past – and one or two are quite well written – I have found none to be especially suitable for the widely varying backgrounds of this audience.

My experience with this audience has led me to conclude that its needs can be met effectively by a book with the following features.

• To meet the needs of computer scientists, the book must teach basic aspects of the structure of DNA, RNA, and proteins, and it must also explain the salient features of the laboratory procedures that give rise to the sorts of data processed by the algorithms selected for the book.

• To meet the needs of biologists, the book must (to some degree) teach programming and include working programs rather than abstract, high-level descriptions of algorithms – yet computer scientists must not become bored with material more appropriate for a basic course in computer programming.

• Justice to the field demands that its statistical aspects be addressed, but the background of the audience demands that these aspects be addressed in a concrete and relatively elementary fashion.