K. Kirk Shung, Ph.D., is Professor of Bioengineering in the Bioengineering Program, Pennsylvania State University, University Park, Pennsylvania. Gary A. Thieme, M.D., is Chief of the Diagnostic Ultrasound Division of the Department of Radiology, The Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania.

• Introduction (K. Kirk Shung). Clinical Relevance of Scattering (Gary Thieme). Biological Tissues as Ultrasonic Scattering Media (K.K. Shung and G. Thieme). Acoustic Scattering Theory Applied to Soft Biological Tissues (M.F. Insana and D.G. Brown). Theoretical Models of Ultrasonic Scattering in Blood (L.Y.L. Mo and R.S.C. Cobbold). Standard Substitution Methods for Measuring Ultrasonic Scattering in Tissues (J.M. Reid). Method of Determination of Acoustic Backscatter and Attenuation Coefficients Independent of Depth and Instrumentation (E.L. Madsen). Measurement System Effects in Ultrasonic Scattering Experiments (R.C. Waag and J.P. Astheimer). In Vitro Experimental Results on Ultrasonic Scattering in Biological Tissues (K.K. Shung). Cardiovascular Tissue Characterization In Vivo (S.A. Wickline, J.E. Perez, and J.G. Miller). In Vivo Liver and Splenic Tissue Characterization by Scattering (Brian Garra). In Vivo Ophthalmological Tissue Characterization by Scattering (F.L. Lizzi and E.J. Fellepa). Fetal Lung Tissue Characterization by Scattering (G.A. Thieme, P.L. Carson, C.R. Meyer, and R. Bowerman). Backscatter Imaging (J. Zagzebski, L.X. Yao, E.J. Boote, and Z.F. Lu). Index.