This book constitutes the Proceedings of the 26th Symposium on Acoustical Imaging held inWindsor, Ontario, Canada during September 9-12, 2001. This traditional scientific event is recognized as a premier forum for the presentation of advanced research results in both theoretical and experimental development. The lAIS was conceived at a 1967Acoustical Holography meeting in the USA. Since then, these traditional symposia provide an opportunity for specialists who are working in this area to make new acquaintances, renew old friendships and present recent results of their research. Our Symposium has grown significantly in size due to a broad interest in various topics and to the quality of the presentations. For the firsttime in 40 years, the IAIS was held in the province of Ontario in Windsor, Canada's Automotive Capital and City of Roses. The 26th IAIS attracted over 100specialists from 13countries representing this interdisciplinary field in physical acoustics, image processing, applied mathematics, solid-state physics, biology and medicine, industrial applications and quality control technologies. The 26th lAIS was organized in the traditional way with only one addition-a Special Session History of Acoustical Imaging with the involvement of such well known scientists as Andrew Briggs, Noriyoshi Chubachi, Robert Green Jr., Joie Jones, Kenneth Erikson, and Bernhard Tittmann. Many of these speakers are well known scientists in their fields and we would like to thank them for making this session extremely successful.