Titus continues her coy series about Sherlock Holmes' mouse counterpart who graduated from Ratcliffe college, takes notes on the master in shortpaw, and pals around with roommate Dr. Dawson. Here Basil takes a few hours to foil the rodent Crown Prince of Crime, Dr. Ratigan in the case of the counterfeit cheese; then he sails off to picturesque Mexico to track down the Mousa Lisa forger who has cheated the national museum. That settled (the curator did it), he caps his fame with a brilliant military defeat of deposed dictator El Bruto, now in league with the sinister Ratigan. There's glowing praise for Basil from every side, and you can hear the author congratulate herself with every corny pun. . . . She's not alone; there's a ""delighted"" letter from Conan Doyle's daughter on the back cover. . . . But we'll wait for Basil's smarter brother.