A string is just a sequence of letters. But strings can be massive. Plant and animal genomes are strings billions of letters long on the simple alphabet Internet traffic among billions of websites is a collection of strings that amount to quadrillions of computer bits every day.

Such strings are regularly searched, probably millions of times a day, for patterns of all kinds - genomic codes for genes and chromosomes, indicators of terrorist activity, and many others. The search for patterns is fundamental to many fields molecular biology, cryptography, data compression, computer vision, speech recognition, computational geometry.

This book provides a basic general introduction to the algorithms (methods) that efficiently compute patterns in strings. It focuses on results that can be explained with reasonable economy and simplicity, but its 250 references also enable the reader to access current state-of-the-art methodology.