This proposal is a joint effort of the Departments of Biology and Psychology and the Neuroscience and Cognitive Science Graduate Program at the University of Maryland, College Park. We have at UMD an exceptional group of 10 faculty with a common research interest in comparative hearing and evolution of hearing. The breadth of experimental approaches and species studies, provides us with an opportunity to provide research training at the graduate and postdoctoral level that exists no where else. At the core of the research training program are 10 funded investigators with proven research and training records, most of whom are located in the same building. There is a strong history of research interaction among this group, and this was further facilitated by the initial five year funding of this training grant. Graduate and postdoctoral students (as well as undergraduates) take advantage of the interaction between faculty and research groups. The proposed program will provide support for four predoctoral and three postdoctoral fellows each year. Two separate but closely related issues are emphasized in our program. The first is that comparative auditory function and structure, and the second is the evolution of the auditory system. The major goal of our program is to produce scientists who have an appreciation for, and an understanding of, the diversity of vertebrate hearing mechanisms and the evolution of the auditory system. We anticipate that the individuals trained in our program will conduct full-time research on evolutionary and/or comparative questions in academic settings. At the very least, our training will ensure that they will be able to put their work into the appropriate content and help add to our growing understanding of these issues. Predoctoral and postdoctoral trainees are recruited nationally. Very importantly, UMD and our participating departments and colleges have strong records of recruiting, retaining, and retention of women and minorities. We continue to take advantage of these opportunities to continue to make recruitment and retention of women and minorities a very important aspect of our program.