“The Boomer Century” (8 p.m., PBS, check local listings) takes yet another look at the most-talked-about generation in human history. They are also the most broadly defined and overgeneralized group of people of all time. And that’s precisely what makes this documentary both interesting and maddening.

As host, psychologist, gerontologist and self-professed bad guitar player Dr. Ken Dychtwald proclaims, boomers arrived in such huge numbers that they could not help change their economy and society. The generation that postponed parenthood during the Depression and World War II began procreating with abandon sometime after VJ Day, and between 1946 and 1964 more than 78 million boomers were born.

Like virtually every book, article or film ever made about the generation, “Century” concentrates most of its attention and formulates virtually all of its generalizations about the oldest boomers, those born in the late 1940s, shaped by the 1950s and who were teens and young adults in the 1960s. And they are just hitting their 60s.

But the vast bulk of boomers are younger, and some have just hit their mid-40s. The oldest boomers had Kennedy’s New Frontier, nuclear families and the Beatles as their formative influences; the youngest had the energy crisis, divorce and the Bay City Rollers. How can you lump together people with such vastly different experiences?

With its focus on 1960s politics, “Century” also ignores how boomer attitudes may have contributed to the conservative shifts of the past decades and how politicians from Ronald Reagan to Newt Gingrich used the rhetoric of “revolution” to appeal to boomers.

“Boomer” does a good job of explaining how the generation has re-created the American workplace and how feminism succeeded in making women accepted in the office and making men feel like equal partners in the child-raising department. The documentary also explains how the generation’s cavalier attitudes toward debt helped provide an engine of economic growth but may be a devastating burden as boomers age.

“Boomer Century” asserts that boomers remain ever optimistic, and Dychtwald seems confident that many will live to see the year 2046. Yikes, that means we still have to endure 40 more years of endless chatter about baby boomers.

Tonight’s other highlights

¢ Matt Damon narrates “Journey to Planet Earth” (7 p.m., PBS, check local listings), focusing on the state of the ocean’s animals.

¢ Jake needs Kenchy to snap out of it and help April through labor on “Jericho” (7 p.m., CBS).

¢ Taylor worries that the players may have lost sight of the game on “Friday Night Lights” (7 p.m., NBC).

¢ A church cemetery becomes a crime scene on “Bones” (7 p.m., Fox).

¢ A pregnant woman has her baby and her life taken from her on “Crossing Jordan” (8 p.m., NBC).

¢ The results are read on “American Idol” (8 p.m., Fox). Gwen Stefani performs.

¢ Allison dreams of demons while Joe fights for a promotion on “Medium” (9 p.m., NBC).

¢ Hurley issues a warning to Sawyer on “Lost” (9 p.m., ABC).