Advanced Texts is a new programme of books published by BIOS, for advanced undergraduates and postgraduates. The books are short concise texts covering advanced topics typically studied in the final year of an undergraduate course or during taught-postgraduate courses. Bioinformatics, the use of computers to address biological questions, has become an essential tool in biological research. It is one of the critical keys needed to unlock the information encoded in the flood of data generated by genome, protein structure, transcriptome and proteome research.