A work of four years (it must be -- see the monumental bibliography), some 400 pages, 16 color and 172 black and white illustrations by the popular scientist, public health oriented conservationist, and regular contributor to various TV and radio shows. Not to mention author, of many books on animals of which his North American Mammals may be more nearly comparable to this -- a book generally accredited for its high level of interest even if one or two scientists managed to pick a nit here and there. Caras' opening chapter on venomous animals is most broadly stimulating: they, by some biological error, have been equipped for overkill; venoms are survival mechanisms produced by special glands, a means to obtain food or to keep from becoming food. The chemistry which Caras can't pursue at an accessible level is inordinately complex; there are many other mysteries as well; and often these deadly species promote their own self-destruct in protecting themselves. From then on this is primarily a labor of taxonomy with associated environmental, evolutionary and public health considerations: from microscopic organisms (marine worms, sponges, etc.) to the coelenterates or stingers in the sea (500 cone shells alone) to the spiders (most are venomous) and scorpions, insects, fish (even that catfish you may have thrown back in the water), snakes (six chapters -- 2700 species) with mammals only very sketchily considered. There are some lists (annual bites and fatalities, etc. -- which are necessarily fallible since most aren't reported), and only occasional personal incidents of envenomation. Exhaustive investigation and fascinating instruction at one and the same time and no doubt an obligatory reference work for all ages.