Here's an Easter greeting that snarls. Baines, weapons manufacturer circa twentieth century, is an artist of destruction. He commissions black magician Theron Ware to murder (a) a California right-wing Governor, (b) a highly placed scientist and (c). . . ? ? ? The final commission scheduled for Easter Sunday opens a surprising Pandora's box and the ending is an unexpected shocker. Mr. Blish has a capricious, deadly sense of humor. One you'll remember.