Virologists have finally embraced the taxonomic concepts of family, genus and species. They have done so with some reluctance, prolonged delay, no little con- troversy and considerable acrimony. Perhaps this explains why the decision has not been well publicized outside the specialist publications of the International Committee of Taxonomy of Viruses (ICTV) and why so many virologists fail to adopt the new approach and carry on much as they did before. It is still not widely appreciated that authors should cite the family name and genus at first mention, as is now done in some publications. The Potyviridae is one of the first virology texts to have been published since the crucial decision was taken. It deals with the 198 viruses ascribed to the family Potyviridae, which comprise three newly recognized genera: Potyvirus (aphid-borne), Bymovirus (mite-borne) and Rymovirus (fungus-borne), together with two provisional genera: Ipomovirus (whitefly-borne) and Macluravirus (aphid-borne). The Potyvirus genus alone contained 82 definite and 98 possible members at the time the book was written and it is the largest of the genera recognized by ICTV It includes such well-known and widely distributed viruses as bean common mosaic, lettuce mosaic, sugarcane mosaic, plum pox and the type member: potato virus Y. Prospective purchasers of the book should take careful note of the title, which makes no mention of the diseases caused by viruses of the Potyviridae. The title is entirely appropriate because the book is concerned almost exclusively with the biochemical properties of the viruses and not with their biology or epidemiology. The restricted approach is apparent from even the most cursory examination of the contents pages and illustrations. There are numerous photographs of virus particles and polyacrylamide gels but only one of virus symptoms in the entire book. A further indication of the approach adopted is that Chapter 2 on ‘Host range, symptomatology and cytopathology’ contains less than half a page on symptoms and no less than 21 on inclusions, including 15 illustrations. Even the final 75-page chapter of ‘Case histories’ contains limited biological information on the 26 viruses selected for special treatment. The preceding 34-page chapter entitled ‘Epidemiology and control strategies’ goes only a little way towards redressing the imbalance. Indeed, it seems to have been added as something of an afterthought and the crucial issue of virus-free planting material is dismissed cursorily in three lines (p. 292)—simply by reference to four previous reviews, one of which is dated 1953! Clearly this book is for the plant virologist and not the plant pathologist or vector ecologist. Instead of belabouring and bemoaning the point it is more appropriate to emphasize the strengths rather than the weaknesses of the book. Its merits lie in the seven central chapters on ‘Transmission’ (21 pp.), ‘Genome structure’ (38 pp.), ‘Coat protein structure’ (35 pp.), ‘Serology’ (28 pp.), ‘Taxonomy’ (31 pp.), ‘Evolution’ (47 pp.) and ‘Diagnosis’ (29 pp.). These provide a wealth of information by the three authors who are acknowledged experts in the field. The Potyviridae weighs in at 1.3 kg and runs to 397 pages of text and no less than 101 pages of references. It is handsomely produced and is so remarkably free from typographical errors that it comes as a surprise to find two on the same page (p. 323). The book will be warmly received by those in laboratory coats and will find a ready place on many shelves. Those with mud on their boots will be less enthusiastic and will regret that the opportunity has been missed to produce a fully comprehensive text covering all aspects of the viruses of the Potyviridae. This review of The Potyviridae is a corrected version of the review published in Plant Pathology47, 225 in which the book was incorrectly referred to as The Phytoyviridae. The reviewer offers his unreserved apology for this error.