The second volume of Universal’s 20th Century Masters: The Millennium Collection compilation of Marvin Gaye’s work focuses on his ’70s hits, including classic tracks like “Mercy Mercy Me (The Ecology),” “What’s Going On,” “Let’s Get It On,” “Trouble Man,” and “You’re a Special Part of Me.” Though it isn’t a complete portrait of his artistry, this collection is an affordable introduction to some of Gaye’s most personal and political singing and songwriting. – Heather Phares