The data compression field has always been an important part of computer science, and it is becoming increasingly popular and important today. Although computers become faster and data storage becomes less expensive and more efficient, the in creased importance of sound and video necessitates the use of at least a small mea sure of data compression due to vast storage and transmission requirements. The question in many applications is now no longer whether to compress data, but what compression method should be applied.

In spite of this growing interest in data compression, there is only a handful of data compression books on the market. Many are technical monographs aimed pri marily at professionals, and they require a fair knowledge of data compression to be intelligible. There is a need for a textbook addressed primarily to undergraduate stu dents (juniors and seniors) of computer science and electrical engineering who already have some data structures and discrete mathematics background.

This is why Elements of Data Compression was written. The goal is to present elementary-level representative method of text, audio, and video compression with the emphasis on presenting these methods with pseudocode, tables, diagrams, and many worked out examples. By necessity, only representative methods are discussed. A truly comprehensive presentation is not possible here because of the immense number of papers and contributions: J. A. Storer compiled a 70-page data compres sion bibliography which, as he says at its preamble, "represents only a very small fraction of the existing data compression research" (Image and Text Compression, Kluwer, 1992).