In public he doesn't exist. In private -- he hangs his hat in special temperature controlled germ-free hotel suites anywhere from Las Vegas to London -- he's called The Man, said to be often comatose, suffering from nutritional anemia and chronic constipation (sometimes sitting an entire day on the toilet), guarded by nurse-secretaries, Mormons -- because they're thought to be less corruptible. Howard Hughes' latest biographer, a Time reporter, attributes Hughes' deteriorating physical and mental condition to jet lag brought on as far back as the early '50's when Hughes, sole owner of Toolco and RKO Pictures among others, reached too high for too large a slice of pie in the sky by borrowing too heavily to bring his TWA in first in a fierce industry race to convert to new jet propelled engines. It's an extraordinarily complex financial and legal story to which Tinnen -- who examined court records, newspaper files and interviewed anyone who'd talk -- devotes the major portion of his book, making all the legalese read with astonishing ease and comprehension -- it did, after all, take the brains of the Supreme Court to get to the nitty-gritty. But before all the litigation ended Hughes was forced to sell Hughes Tool, lost control of TWA and was in turn sued by them on an anti-trust technicality -- they were awarded $145,448,141.07 -- no small potatoes even for one of the richest men in the world -- even though that judgment was resolved finally in Hughes' favor on a second appeal to the high court and dismissed in January 1973 just weeks after Hughes' 67th birthday. The cost to Hughes in legal fees is estimated at at least $20 million, or $17,000 per diem. There's not much covered here to titillate those who love a good gossip, aside from a chapter on the Irving brouhaha -- still it's a book that soars along with all engines firing.