A solidly written, always interesting book of travel by a master explorer. Ridgeway (The Last Step, 1980), who is perhaps best known as a mountaineer and mountaineering journalist, confesses at the opening of his new book that he would gladly trade in, if need be, all his ascents for the chance to take more long walks across open country--plains, savannas, deserts. He recently decided to indulge this passion by making a trek across the grasslands of East Africa, wishing, as he writes, ""to see what it would be like to walk for an extended period in the close company of potentially dangerous mammals."" (Among the mammals that figure in his narrative are lions, leopards, elephants, and rhinos, all of which, made cranky by an intense drought, give him a good scare or two.) Starting with an ascent, naturally, of Kilimanjaro, Ridgeway takes in a broad sweep of country, writing about it with keen awareness and undisguised affection. He paints colorful scenes in vivid (and occasionally vulgar) language, and those scenes effectively convey the difficulty of his journey without descending into the macho bravado so common to adventure-travel writing: ""We weave through the dun-colored bush like puff adders,"" he writes in a typical passage, ""threading through one opening, then, without thinking, making for the next hole, lifting delicately a branch lined with two-inch thorns and easing it back so it doesn't slap and puncture the person behind."" Writers who travel in the shadow of Kilimanjaro necessarily travel in the shadow of Ernest Hemingway, the master of that bravado; Ridgeway wisely uses Hemingway and other writers--Isak Dinesen and Peter Beard among them--as foils, measuring what they had to say against his own experiences, gently correcting and augmenting their words. Those experiences inform an entertaining and literate memoir of backcountry adventure.