'Data acquisition' is concerned with taking one or more analogue signals and converting them to digital form with sufficient accu racy and speed to be ready for processing by a computer. The increasing use of computers makes this an expanding field, and it is important that the conversion process is done correctly because information lost at this stage can never be regained, no matter how good the computation. The old saying - garbage in, garbage out - is very relevant to data acquisition, and so every part of the book contains a discussion of errors: where do they come from, how large are they, and what can be done to reduce them? The book aims to treat the data acquisition process in depth with less detailed chapters on the fundamental principles of measure ment, sensors and signal conditioning. There is also a chapter on software packages, which are becoming increasingly popular. This is such a rapidly changing topic that any review of available pro grams is bound to be out of date before the book reaches the read ers. For this reason, I have described the data handling which is available in various types of program and left it to the reader to select from whatever is on the market at the time.