This book provides guidelines for the use of structured observations. Structured observations are a method to measure behaviour. Measurement of behaviour is indicated in a number of situations for the planning, implementation and evaluation of health intervention projects. As structured observations are like a cog in a machine it is necessary to first picture the general framework in which they are used. This is done in Part One of the book. Part Two covers general research design issues, and Part Three provides a step-by-step guide for the use of structured observations. The audience for these guidelines comprises social scientists and others with a research background, who wish to consider structured observations as part of a health behaviour study, especially if the study is in support of a proposed or existing health intervention project. The terms 'programme' and 'project' are used interchangeably, as the difference between the two is irrelevant for the purposes of this book.