Leonard Bernstein wrote this television essay in 1985 to celebrate the 125th birthday of legendary composer Gustav Mahler. In addition to his own commentary, Bernstein uses 17 years' worth of performances to illuminate the roots of Mahler's genius, conducting the Israel, London and Vienna Philharmonic orchestras in excerpts from Mahler's nine symphonies as well as "The Song of the Earth" and the "Wunderhorn Cycle" (for solo vocalists and orchestra).