This book describes the methods and attributes required for the compe tent quality control of the data acquisition of a seismic exploration crew operating on land. Although the book is concerned mainly with explo ration for oil and gas reservoirs, and all the topics that are discussed in it are centred on that target, the material is applicable to other areas of seismic exploration such as civil engineering and the search for other minerals. The book comprises the distillation of more than thirty years' experience in geophysical exploration in all its aspects and in many parts of the world. Seismic data acquisition quality supervision is one aspect of geophysical exploration which, although of great importance, has had, so far as the writer is aware, no textbook devoted to it. It is hoped that it will be of interest to anyone who is engaged, in whatever capacity, in geophysical exploration and will help them to attain their goal, which is illustrated in Fig. 1. 1. The term birddog is colloquial in the geophysical exploration industry. It is a convenient shorthand title to describe the person whose full title is, and who acts as, the data acquisition quality control supervisor on a field seismic exploration crew. The term is used also to describe the person who is the client's representative on the field crew. In practice the same person performs both functions on behalf of the client.