artin Amis's ''Koba the Dread'' has got to be one of the oddest books about Stalin ever written, indignant, angry, personal and strangely touching. Amis has read what he describes as ''several yards of books about the Soviet experiment,'' including ones by Aleksandr Solzhenitsyn, Robert Conquest, Vasily Grossman and Dmitri Volkogonov -- a small but choice percentage of the vast literature on Stalin and his crimes. Having digested those several yards, Amis sets out to summarize Stalin's lies and murders (which he figures at roughly 20 million), the prison system, the slave labor projects, the purges and show trials...