The techniques and usefulness of broadcasting sounds to wild animals and watching their response, are explored in 15 papers from an August 1991 workshop near Chesterfield, England. Controversies are aired as to the validity of the experiment and of various methods and interpretations; new equipment, techniques, and considerations are also reported. Among the topics are the integration of playback findings into larger studies, call-timing in male-male interactions in frogs, and comparison between laboratory and field studies. Most of the papers are concerned with birds. Annotation c. by Book News, Inc., Portland, Or.