Cheerful political tidings from a state best known these days for its homegrown militias. Kemmis, the mayor of Missoula, Mont., writes that only the active involvement of the citizenry can make our cities better places to live. That's not news. What is news is his belief that the most active citizens ought to spend more time at home tending their own gardens. Kemmis urges city planners and politicians to create mechanisms that encourage involvement by everyone, not just the civic-minded few, arguing that cities should not prosper ""at the expense of the health and sanity of their citizens"" and reminding us that the ""organic vitality"" of cities sometimes just happens out of accumulated goodwill--with or without intervention or planning. Missoula, of course, is not New York or Los Angeles, and critics may justly question Kemmis's sometimes touchy-feely notions of how burgs operate. Kemmis has done his homework, however, and points out just how things can be better in small and big cities alike. One of the pleasures of his book is his detailed account of the history and workings of international sister-cities programs--Missoula has like-sized sisters in Germany and Japan--and how the exchange of citizens from all walks of life does more to enrich understanding than a barrel of political nostrums. Quoting from Aristotle and Plutarch, Kemmis urges an encompassing vision of city life that will remind readers of Marshall McLuhan, Lewis Mumford, Jane Jacobs, and other urban visionaries. His book, happily, fares well in that company. Big Sky blue-skying abounds here, to be sure, but Kemmis offers many good ideas that merit a hearing outside his own city's gates.