Molecular Mechanisms in Striated Muscle . By S. V. Perry. (Pp. x+168; illustrated in colour and black & white; £35/$59.95 hardback, £12.95/$19.95 paperback; ISBN 0 521 57001 8 hardback, 0 521 57916 3 paperback.) Cambridge: Cambridge University Press. 1996.

This short book is a summary of lectures Professor Perry gave under the auspices of the Accademia Nazionale dei Lincei sponsored by the IBM Foundation of Italy. Professor Perry FRS is regarded as one of the fathers of muscle biochemistry. In particular he is an authority on activation}contraction coupling of skeletal muscles with particular reference to the regulatory proteins. These undergo a transformational change to expose the active sites on the thin filaments so that the myosin crossbridges can engage and generate force. Much of the book is concerned with the way in which the myosin molecular motors generate force. However, the 1st chapter deals with general aspects of motile systems and compares and contrasts the actin-based motor protein systems with the tubulin-based motor protein systems in eukaryotes. Cell motility in procaryotes is only briefly mentioned with a brief reference to the rotary motors in flagella. Elucidation of the structure of the head (S1) of the myosin crossbridges by -ray diffraction and the previous knowledge of the structure of the thin (actin) filament has made it possible to postulate mechanisms involved in the steps in the crossbridge cycle. As mentioned, much of the book (Chapters 3, 4 and 5) is concerned with the switching on and switching off of the myofibrillar system; the last chapter (6) is devoted to a description of Duchenne muscular dystrophy and the generalised structure of dystrophin (the protein that is missing in this form of muscular dystrophy). This is based on work published in 1991 and is therefore somewhat outof-date. For example, dystrophin is no longer thought to be a double molecule. Also it does not fit in with the general theme of the book because as yet no mechanism or role has been assigned to dystrophin except insofar as it is a cytoskeletal protein that reinforces the membrane. Muscle is a mechanical tissue and for the morphologist there is insufficient detail of the structural aspects of contraction. For example there has been some recent work which uses ultrahigh resolution electronmicroscopy to look at the myosin crossbridges in muscle frozen at different stages of contraction. The structure of the sarcoplasmic reticulum and T tubule systems is, however, very informative. The molecular structure of the myosin crossbridge head (S1) is of considerable interest as is the discussion of the nonmuscle myosins and the variations found between the different classes of myosin, e.g. some exist as just single S1 heads, others have 2 heads but no rods, and others (including the conventional muscle myosins) consist of double structures with 2 heads and 2 rods. At the present time there are about 12 classes of myosins of which only class II are the conventional or muscle myosins. The existence of these myosin molecular motors in many cell types emphasises the universality of these molecular motors. The book is reasonably priced and it is an easy-to-read description of our present-day knowledge of how skeletal muscle works. Therefore it could be recommended reading for science students specialising in physiology or medical and veterinary students pursuing special option courses in musculoskeletal biology. It is certainly a book that should be purchased by most university libraries. .