Bill Moyers, whose weekly magazine-style show, Now, on PBS has capped his 30-year career in TV journalism, is leaving the broadcast after the November elections.

His next venture: Writing a long-planned book about Lyndon Johnson, whom he once served.

"It isn't because I feel old," Moyers, 69, said of his decision to move on. "It's because I feel compelled to do something else now, that only I can do - which is that book."

Now is a diverse mix of reports and in-studio interviews whose aim, in Moyers' words, "is to tell stories nobody else is telling and put on people who have no forum elsewhere."