Rex Whistler — this book’s ‘bright young thing’ — was an artist of the 1920s and 1930s, and Edith Olivier, the ‘bluestocking’, was a novelist. They both deserve to be more famous than they are, and Anna Thomasson’s absorbing joint biography will doubtless make them so. They met through Stephen Tennant in 1924, when Olivier was 51 and Whistler was a 19-year-old student at what he called ‘the darling Slade’.