With your Lehanes, Pelecanoses, and Prices spinning gritty ultra-realism into (deserved) critical glory, James Ellroy seems a little out-of-step with the current mystery/thriller zeitgeist; but to ignore the old Demon Dog now is your own loss. Tonight, Ellroy reads from and signs Blood's a Rover, the final installment of his "Underworld USA" trilogy. J. Edgar Hoover, Howard Hughes, and Richard Nixon rub shoulders with Ellroy's usual cast of "peepers, prowlers, pederasts, panty-sniffers, punks, and pimps." Still, as with American Tabloid and The Cold Six Thousand, "alternate history" seems too fantastical for Ellroy's calculated liberties. "The LA Quartet" remains the best intro, but Blood's hardboiled conspiracy-noir is as rewarding as it is dense — and a fine capstone to Ellroy's most ambitious collection.