Inadequacies of the classical science of tissue morphology based on conventional microscopy were evident long before the advent of modern, integrated morphology. These inadequacies resulted mainly from the static nature of classical morphology: a cell or tissue studied by the conventional light microscope is not very informative about its past, its future functional or developmental capacities, and even its present functional state. Before the development of integrated approaches to morphology, the most of what could be said about these aspects of cellular biology was based on speculation (and sometimes imagination), so that the morphological science was gradually transformed into an art. During the past two decades, the advent of new techniques, such as the use of tracer isotopes, high-resolution autoradiography, improvements in tissue culture methods, correlation of in vitro and in vivo models, extensive use of biophysical and biochemical methods, and higher-resolution microscopy have transformed classical morphology into an integrated