Pierre Boulez at 90: His Top Five Transformations

From WQXR:

This week the composer, conductor and musical éminence grise, Pierre Boulez, celebrates his 90th birthday with events around the world. We’ve delved into our our archives to revive several interviews chronicling his career, and one constant throughout is Boulez’s perpetual interest in revising and expanding his previous works. Here are five pieces that Boulez has and continues to transform.