This volume is intended to cover research in the field of muscle morphology since publication of the previous edition by Haggquist in 1956. The development of new techniques, coupled with an intensified interest in muscle, has resulted in a vast literature which no single person could review, especially within the limitations of one volume. When I accepted the flattering offer to write a new edition, I quickly abandoned any hope of a comprehensive review. Instead, I tried to consider, within my limits, those lines of research which I believe to be important for the understanding of mammalian and ultimately human muscles under normal, experimental, and pathological conditions. It would be naive to suggest that muscle can be adequately described in purely morphologi­ cal aspects; I would characterize the results of my effort as "muscle as seen with the eyes of a morphologist". It gives me pleasure to acknowledge the help of several colleagues who read and commented on drafts of individual chapters: Dr. Brenda Eisenberg, Chicago; Dr. Else Nygaard, Copenhagen; Dr. Stefano Schiaffino, Padova; Dr. Michael Sjostrom, Umea; Dr. Lars~Erik Thornell, Umea. None of these individ­ uals can be held responsible for any error or obscurity that persists. Indeed, without their assistance there would have been more. I also thank those col­ leagues who allowed me to include their published and unpublished material; their names, and also those of the publishers who kindly granted copyright permission, are given in the individual figure captions.