Sleepless Nights, by Elizabeth Hardwick. New York: Vintage. $2.50.

This is a dignified, generous, and humane work; a record of a life consisting of freshly reassembled people and events transfigured by a sometimes pained but always loving memory. In this novel, Elizabeth Hardwick has written a sort of nocturnal journal of the revisiting she does during her sleepless nights when, as she puts it, she is "always waking up to address myself to B. and D. and C. -- those whom I dare not ring up until morning and yet must talk to throughout the night."