The title, which conjures up thoughts of ""Know Your Hyena,"" gives a misleading idea of this sensible pet-owner's manual. Dolensek, chief veterinarian at the Bronx Zoo, knows that the first-hyena-on-the-block impulse will sometimes prevail over the interests of family, furniture, neighbors, or the beast itself. He is not about to encourage it. The first half of the book is a three-part survey of pets usual and unusual. ""Easy"" and ""difficult"" pets can be misery enough to owners with impractical attitudes. ""Impossible"" ones include all primates, wild rodents, big cats, deer, and wild canines. Dolensek offers advice--discouraging advice--to people who have been silly enough to tangle with these poor creatures, in the spirit of a school nurse treating someone who stuck a bean up his nose. The book's second half deals with pet ownership, from choosing the animal to the final parting of the ways. Dolensek discusses checking the condition of a prospective puppy or guinea pig, adjusting the animal to the household or--within the bounds of sanity--vice versa, appropriate pen or cage arrangements, the rearing of babies, preventive medical care, disposing of mortal remains. An appendix conveniently tabulates relevant facts (life span, adult weight range, etc.) about each species. As a reference work, broad rather than specific; as an orientation course, chipper and intelligent.