Short answers, pulled from the story.
The Lord of the Rings 1981 radio series first aired on BBC Radio 4 from the 8th of March to the 30th of August 1981, with new episodes broadcast on Sundays at 12 noon and repeated the following Wednesday night.
Brian Sibley and Michael Bakewell wrote the Lord of the Rings 1981 radio series, dividing the scriptwriting across its 26 episodes at the BBC's request.
Ian Holm played Frodo Baggins and Michael Hordern played Gandalf in the Lord of the Rings 1981 radio series. Writer Brian Sibley called Holm's casting 'simply inspired.'
The Lord of the Rings 1981 radio series leaves out Tom Bombadil, along with Crickhollow, the Old Forest, and the Barrow-wights, because writer Brian Sibley judged Bombadil a character Tolkien created independently of the novel. He chose to excise the whole episode rather than dramatically reduce several others.
The Lord of the Rings 1981 radio series ran for 26 half-hour episodes. It was later re-edited into 13 hour-long episodes broadcast from the 17th of July to the 9th of October 1982.
The BBC reissued the Lord of the Rings 1981 radio series in three audiobook sets following the success of Peter Jackson's The Lord of the Rings film trilogy in the early 2000s. The reissue added new monologues written by Brian Sibley and read by Ian Holm.