New York Times (In Short): [This] new novel is about a man who is not nearly so easy to know [as the protaganist in The Ugly American]. When the best- selling author George Adamson, who employs the Greek spelling of his name - Giorghos - in this story, arrives in Greece, he is feeling out of shape and insecure and is almost immediately humbled by a marvelously warm, wise and strong woman named Maria. She makes him painfully aware of some of his flaws. On impulse, he buys an ancient red caique, reluctantly takes on board two men with stronger presences than his own - interesting, offbeat characters both of them - and sets out to the islands. He learns something about himself during a storm at sea and an unfortunate scrape with a much bigger boat, from visits to monasteries to research the book he is writing and from lectures by his two passengers. One thing they tell him is, ''God is everything, and therefore God can't define God. That's why God needs man.