A research project entitled Biomechanics of Structure and Function of Living Cells, Tissues, and Organs was launched in Japan in 1992. This data book presents the original, up-to-date information resulting from the research project, supplemented by some of the important basic data published previously. The aim of collecting the information is to offer accurate and useful data on the mechanical properties of living materials to biomechanical scientists, biomedical engineers, medical scientists, and clinicians. The data are presented in graphs and tables (one type of data per page) arranged in an easily accessible manner, along with details of the origin of the material and the experimental method. Together with its two companion volumes, Biomechanics: Functional Adaptation and Remodeling and Computational Biomechanics, the Data Book on Mechanical Properties of Living Cells, Tissues, and Organs is a timely and valuable contribution to the rapidly growing field of biomechanics.