Nature (PBS, 8-9 p.m.): This edition of the noted series will take some getting used to. Don't expect standard wildlife shots. Don't even expect narration. ``Anima Mundi,'' the first half of the program, is the lyrical and highly personal vision of a noted filmmaking team: director Godfrey Reggio and renowned composer Philip Glass, who wrote the score. The film's poetic flow of sound and images is designed to evoke the diversity of nature and mankind's impact on it.
A clue about the film's tone is a statement by Plato that appears on the screen in several languages: ``This world is indeed a living being endowed with soul and intelligence.''
``Anima Mundi'' is followed by a feature called ``Before It's Too Late,'' about efforts by zoos around the world to protect endangered species.
Booknotes (C-Span, 8-9 p.m.): The guest is Gary Hymel, co-author (with the late Tip O'Neil, former Speaker of the House) of ``All Politics Is Local and Other Rules of the Game.''
Pavarotti Plus! (PBS, 9-11 p.m., EST): What's different about this TV appearance by the great tenor Luciano Pavarotti is the intermission. It includes ``Backstage/Lincoln Center,'' a new documentary feature hosted by pianist Andre Watts and comprising two segments. One takes a nimble, multifaceted look at stage fright; the other asks why tenors and sopranos - rather than, say, baritones - are the world's vocal stars. (Pavarotti's concise explanation: Tenor singing is ``more exciting because it is more dangerous.'')
``Backstage/Lincoln Center'' will also air separately on many stations (check local listings) in a fuller version that includes a third segment about how singers preserve their voices and careers.
All three segments are fast-paced essays that evocatively intercut old and new performance clips and other scenes, and also offer knowledgeable comments from many fronts. The result is a whirlwind look at the sacrifice and dedication behind those stunning vocal performances that are made to look so easy by the great artists.
Please check local listings for these programs.