By Chris Nashawaty
Updated March 12, 2015 at 12:00 PM EDT
Magnolia Pictures

With its release held up for seven years because of rights issues, Denny Tedesco’s illuminating documentary about the unsung L.A. session musicians who provided the backbeat for some of the greatest songs from the ’50s through the ’80s can now be seen. The wait was worth it. Hal Blaine, Earl Palmer, Carol Kaye, and the director’s dad, Tommy Tedesco, are finally allowed to step out of the shadows and take a belated bow. B+