BIRDS OF AMERICA by Mary McCarthy. 344 pages. Harcourt Brace Jovanovich. $6.95.
It has been seven years since Mary McCarthy published The Group, her witty, intricate chorale of the '30s, which was praised at the cash registers and patronized by the critics as a popular piece of junk. Such a misunderstanding is unlikely to befall her ambitious new book. Birds of America is so deeply plunged in thought that, despite attractive characters and immaculately constructed scenes, it often seems less like a novel than one of the author's admirable essays. The principal thinker, whose mind frames and filters the events, is...