What Good is a Cactus?

This unfocused amalgam of nature study, mystical philosophy and discursive story will surely be over the heads of its intended audience. The cactus's role in nature is sought out by the book's protagonist (``Permit me to introduce myself. I am Poco, the curious scientist''), who, having been asked the title question, sets off to find the answer. The Native American Albert Redcloud offers some information and suggests that Poco consult the raven--which ``will not speak to you, of course . . . but if you watch closely, it will show you what you want to know.'' Poco encounters the bird: ``I followed the outstretched wings intently, letting my spirit fly after the raven wherever it would go, becoming in my mind the very soul of the Great Bird of the Desert.'' An unmistakably didactic tone may further alienate the reader. Brown's handsome, scumbled artwork adds the requisite atmosphere but otherwise does little to advance or amplify the book's content. Ages 6-10. (July)