Whimsey upon whimsey--with lots of inaccessible parody and only one frail thread of emotional continuity. On a dull afternoon, the little girl narrator's teddy bear produces his scrapbook--with pictures of himself in various adventurous guises. Then we have, in his words (and the appropriate idiom), the story of Teddy the cowboy's fall at the rodeo (to the dismay of golden-haired Melissa); Teddy the explorer's brush with the Abominable Snowman (a gentlemanly British bear--""except maybe one with a glandular problem""--once abandoned on Hampstead Heath); Teddy the clown's rescue of an imperiled tightrope-walker (golden-haired Miranda); Teddy the reporter's solution of the Case of the Missing Milk Money (which involves a bit of Freudian analysis); and the stories of Teddy the chef and Teddy the movie star--which involve golden-haired girls named Mimi and Melinda respectively. The latter also involves Teddy in a rivalry with Lassie that's one of the few down-home jokes here. But better still is the narrator's jealousy of each of Teddy's golden-haired admirers--until he assures her that her love for him, in his old and shabby state, is ""an even greater love."" And the book closes with a picture of a little girl with straight brown hair clutching a plain old patched teddy bear. Trouble is, few youngsters of the indicated age will get that far.