This guide is designed to alert readers to the scope and variety of programming coming up. Listing is not meant to represent blanket endorsement. Viewers are urged to be selective. FRIDAY On Stage at Wolf Trap (PBS, 9-10 p.m.): Broadway performer Maureen McGovern sings her hits and lesser-known numbers from the stage at festival site outside Washington, D.C. Ain't Nothin' But the Blues (PBS, 10-11 p.m.): Talk and performance trace the richly textured history of this musical form and its impact on American culture.
SATURDAY NBA Playoffs (CBS, 3:30-6 p.m.): Check local listings for competing teams, as pro basketball narrows the field toward the finals.
SUNDAY Citizen Summit (PBS, 10-11 p.m.): Soviet advisers - including some who will work with Gorbachev at the coming summit - and an American team discuss crucial issues. Moderated by Hodding Carter III. NBA Playoffs (CBS, 1-3:30 p.m.): Check local listings for competing pro basketball teams and starting times. Spirit of Adventure (ABC, 5-6 p.m.): ``Africa's Poaching Wars'' looks at the alarming decimation of the elephant and black rhinoceros and the struggle to preserve these species.
MONDAY Ring of Fire (PBS, 8-9 p.m.): ``Dance of the Warriors'' - second part of series following the Blair brothers on their journey through the Indonesian Archipelago and beyond. An Ocean Apart (PBS, 9-10 p.m.): Part 2 of series on US-British relations looks at economies of the two nations in the '20s. Moyers: Joseph Campbell and the Power of Myth (PBS, 10-11 p.m.): Premi`ere of series with Bill Moyers interviewing the late teacher and storyteller, whose writing on myth and ritual has influenced Western culture.
TUESDAY Frontline (PBS, 9-10 p.m.): ``The Defense of Europe'' considers how the NATO alliance will adjust to the US-Soviet nuclear arms treaty. Monuments to Failure: America's Prison Crisis (PBS, 10-11 p.m.): This mounting national problem is analyzed by New York Times columnist Tom Wicker.
WEDNESDAY American Playhouse (PBS, 9-10 p.m.): ``Land of Little Rain'' is a biography of American writer Mary Austin, who had a deep affinity for American Indian culture. California Presidential Primary Debate (PBS, 10-11:30 p.m.): Michael Dukakis and Jesse Jackson are among those included in this live coverage from San Francisco 10 days before this state's primary. Secrets of the Jungle Caves (A&E/cable, premi`ering 9 p.m.): Latest stop in the ongoing ``Living Dangerously'' series covers British expedition to Papua New Guinea.
Schedules may vary in some time zones. Please check local listings, especially for PBS, where individual stations often air programs on differing days and times.