An immensely important area, this introduction to computer networking covers everything from systems linked by telephone lines to tightly coupled networks of processors using high speed lines, and the correspondingly broad range of techniques that are needed. The emphasis lies on understanding the principles involved, rather than being bound to specific systems or protocols that may rapidly become out of date. A detailed discussion of standards and systems is given where they are widely accepted and likely to be long-lasting. In particular the ARPANET and OSI standards are explained. The author's style is extremely accessible, and many "real-life" examples illustrate the text.