J. J. Videler. 2005. Oxford Ornithology Series, Oxford University Press, Oxford. xv + 258 pp., numerous black-and-white line drawings and a few black-and-white photographs. ISBN 0-19-856603-4. Cloth, $114.50.- Although the subject of bird flight has enjoyed both popular and scientific attention for several hundred years, the past 25 years have witnessed an explosion of published information addressing the functional anatomy, physiology, physics, and evolution of animal flight. This is primarily attributable to advances in recording technology (e.g., micro-biomechanical implants, fluid flow visualization, high-speed digital video, cineradiography, electron microscopy, and satellite telemetry and radiotelemetry) as well as recent discoveries of extraordinary paleontological material. Such activities are stimulating reevaluation of traditional hypotheses regarding the origin and evolution of flight in birds. J. J. Videler has distilled this vast array of new information into a timely and important volume.

Videler holds the Leonardo da Vinci Professorship of Marine Zoology at the University of Groningen, The Netherlands. His research program has focused on the locomotor biology of vertebrates, specifically fishes and birds, as they move through fluids. His love of natural history and his scientific capacity in the lab make him well prepared to evaluate and summarize the literature surrounding avian flight.

In the opening chapter, Videler provides a historical account of key contributions made over the past three centuries that are relevant to the subject of bird flight. He succinctly recounts efforts made by naturalists, biologists, mechanical and fluid physicists, and pioneering aeronauts to illustrate how each investigator built upon the physical or biological discoveries of his predecessors.

Two chapters concentrate on the internal and external machinery (e.g., musculoskeletal system and feathers) of the avian flight apparatus. Although the feather chapter is thorough and detailed (including numerous illustrations and scanning electron micrographs), there is a notable lack of reference to seminal work on feather growth, phylogeny, and evolution published over the past two decades (e.g., there is no discussion of the work of R. Prum and associates).

Another chapter reviews the basics of aerodynamics, with an emphasis on flow visualization. This includes Kokshaysky's classic study on the visualization of air flow generated by a bird's wing flying through dust, along with Rayner and Spedding's studies employing neutrally buoyant soap bubbles filled with helium, recorded using stereo-photography. A brief discussion is offered of current state-of-the-art flow visualization techniques (digital particle image velicometry) using lasers and high-speed video that visually capture and compute impulse vortices created by the flapping wings of flying birds (Spedding and associates at the Lund laboratory). Videler highlights his recent work on the leading-edge vortices (LEVs) created by swift, fixed wings.

Unfortunately, the chapter on the evolution of flight is dominated by Videler's admittedly controversial theory. Videler hypothesizes that Archaeopteryx locomoted by running on water, as observed in extant basilisk lizards (Jesus Christ lizard [Chrisbala cherepo basilisk]) of Central and South America, and further postulates that this locomotor mode may have represented a transitional stage leading to flight. From my point of view, and I am admittedly not a neutral player in this arena, this is the most disappointing section of the book. His hypothesis, like most other hypotheses on the origin of bird flight, is non- testable, highly speculative, and—even if we accept it—does not really take us beyond a gliding phase or explain powered, flapping flight. Common to this and most other hypotheses on flight, there is no plausible explanation of adaptive transitional forms. I applaud Videler for his valiant attempt to provide a stepwise construct of the morphological, biomechanical, and aerodynamic parameters of his theory. However, this chapter on evolution would have benefited greatly by even a cursory review of other hypotheses and, particularly, those that integrate various disciplines (e.g., paleontological, ecological, ontogenetic, and aerodynamic data) relevant to the origin of flight.

The remaining chapters are excellent, concentrating on different modes of flight and details of the skeletomuscular flight apparatus. Here, Videler does what no previous book on flight has been able to accomplish—he vividly assembles and distills the intricate components of the avian flight system and supplements this with current and past research. The book concludes with two fine chapters dedicated to discussions on the energy required for flight and comparative metabolic studies of avian flight. These chapters are well organized and provide a balanced review of the vast amount of information on these topics.

My overall evaluation of the text is that it is an important and valuable addition to the library of anyone interested in animal locomotion and bird flight. In an effort to provide constructive criticism for potential future editions, I suggest the following: (1) the writing is rather stilted and dense, almost encyclopedic, and would have benefited greatly by using the engaging narrative style found in the preface; (2) although it is perfectly fine to showcase one's work in one's own book, the evolution-of-flight chapter would have benefited greatly from inclusion of current literature on this dynamic subject; and (3) the editor could have been more vigilant in regard to spelling and the clarity of some of the figures.

Avian Flight will particularly benefit upper-division undergraduates, all graduate students, and researchers wanting to ramp-up to the vast body of information now available on avian locomotion. I particularly recommend the book to those interested in general vertebrate locomotion and those interested in the integration of form and function into the ecology and evolution of birds.