Noël Coward’s letters are a roll call of twentieth-century literary, theatrical, and cinematic big shots: George Bernard Shaw, Virginia Woolf (who instructed him to “drop Woolf — stick to Virginia”), Greta Garbo, and Marlene Dietrich. Their tone is English to a T (everyone is “darling”; his sign-off is “Snoopie”), and his observations, ultratart (on Proust: “He is worth reading but Oh la la, how jolly tiresome”). This book is liberally sprinkled with photos of the arch toff trotting across the globe, but the cover shot, of an elegantly suited Coward gently reclining, cigarette in hand, gazing into the distance, best suggests how one enjoy these letters — by savoring them, slowly.