‘A genre-defying monument’: how Sign o’ the Times captured Prince at his creative peak

<p>As a new book on the Paisley Park polymath is released, author John McKie explains why Prince’s 1987 album is the ultimate showcase of his genius</p><p>By the early 1980s, <a href="https://www.theguardian.com/music/prince">Prince</a> had cemented his place as a pop h