Once labelled the bad boy of American classical music, Michael Tilson Thomas long ago established himself as a conductor of uncommon sensitivity. His heightened communication abilities have brought out the best of the many orchestras he’s either led or served as a guest conductor. Just as important have been his catholic sensibility and fierce dedication to including 20th-century music—Ives, Stockhausen and Lou Harrison among more recent work—eschewed by most American symphonies. Thomas became music director of the San Francisco Symphony in 1995, and his programming there celebrates great music regardless of style or school, perpetually balancing zeal and rigour.