The 1956 edition of this book may be regarded as seminal within sociology, spawning a whole field of qualitative opinion research that has continued to evolve through half a century of inquiry. This is a reissue of the book, with a new preface by Merton, a select bibliography of writings on the focused interview and focus group research, and a new introduction that traces the diffusion of Merton's technique from sociology to other fields, including history, psychology, mass media and marketing research.