This collection of short crime stories offers five courses of delectable depravity from mystery's master chef.   Playing Othello is hard on any actor, but for the great James Dragon, the role is toxic. During the play's run, he must reenact the horrible crime that took his own wife's life. Every person in the audience thinks that Dragon killed his real-life wife, and when the curtain rises they wonder if tonight will be the night when Othello finally cracks.   "After the Event" is just the first in a round of Cockrill cocktails--bracing short fiction starring Christianna Brand's famed Scotland Yard inspector. From there we proceed to bloody entrees, chilling desserts, and a cup of black coffee that will shock you wide awake. Brand's short fiction is more than a sample--it is an all-night banquet that leaves the reader terrified and satisfied as only a good mystery can.