In his new memoir, “Take My Word for It,” Burton shares the trials behind his soothing voice and Mr. Rogers–esque reputation. We see him as a teen seminarian angry about his G.I. father’s absence, seeking structure and community first in religion, and then in dreams of fame on Broadway. He revisits the heady days of his post-“Roots” celebrity, from experiments with hallucinogens to manic episodes that were later diagnosed as symptoms of bipolar disorder.