When James Whistler was two years old, he was asked why he’d disappeared from company and hidden under a table. ‘I’s drawrin,’ he replied. He started as he meant to go on. Daniel E. Sutherland’s well-appointed new biography of the American-born painter — whom Henry James described as a ‘queer little Londonised Southerner’ — keeps the attention there, making its central emphasis Whistler’s ferocious single-mindedness in the making of his art.