Over the past several years, "the American in Tuscany" has become a literary subgenre. Launched by the phenomenal success of Frances Mayes's Under the Tuscan Sun, bookstores now burgeon with nimble, witty accounts of this clash in cultures-Americans trying to do American things in Italy and bumping against a brick wall of tradition.Too Much Tuscan Sun is Dario's, a Tuscan guide whose client base is predominantly American, account of some of his more remarkable customers, from the obsessive and the oblivious to the downright lunatic.