If the British actress Gertrude Lawrence is remembered at all nowadays, it is primarily for originating the part of Anna Leonowens in Rodgers and Hammerstein’s The King and I (1951). She didn’t get the role in the 1956 film, and her reputation rests on a long theatrical career in Britain and America, as Lucy Stevens’s gossipy Gertrude Lawrence: A Lovely Way to Spend an Evening, makes clear.