Book excerpt: Well, it's about time (and why did it have to come from the "left" press?) that someone called to account all the smug Kremlinologists who insisted, either ignorantly or deviously, that the Soviet Union could never change. Here are the changes--and how the Kremlinologists missed them. Much of this volume has been previously published. No bibliography or notes. (RC) Annotation copyrighted by Book News, Inc., Portland, OR