Regeneration of skeletal muscle has often been described during the past century, but only during the past 25 years have attempts been made to uncover causal mechanisms underlying the process. The historical and classical histological aspects of skeletal muscle regeneration have been reviewed several times (Studitsky and Striganova,'51; Godman,'57; Field,'60; Betz et al.,'66). Here I shall attempt to synthesize the results of the major experimental studies as well as place into sharper focus some of the new problems which have stemmed from electron microscopic investigations of the past decade.

With respect to both control mechanisms and certain morphological aspects of regeneration, considerable confusion has reigned in the past because events occurring in the repair of damaged mammalian muscle have been equated with those which take place in the regenerating amphibian limb. One of the major functions of this review will be to point out where similarities between these two processes may exist and where the systems are not directly comparable. The review will conclude with a short discussion about the clinical implications of recent progress in the field of muscle regenera tion.