The man who made late night TV what it is for 30 years, now nearly forgotten by younger audiences, is given his due in a fascinating and thorough biography on “American Masters” (PBS, 9 p.m., check local listings).

“Johnny Carson: King of Late Night” was made with lots of incisive interviews with one of his wives, many of his guests, and a whole lot of confessional excerpts from his late night shows, which it must have taken thousands of hours to find and compile.

The picture is someone who is a consummate entertainer, but had little left for those in his personal life; who found he could never please his mother, and had a tough time keeping a marriage together – a person that millions knew and revered, but maybe nobody knew intimately well.

The portrait comes on a comparatively huge night on network TV, that includes the anticipated season premiere of “America’s Got Talent” (NBC, 8 p.m.), which includes Howard Stern as the new judge – a vast improvement on Piers Morgan who will succeed in bringing a brash honesty to the proceedings. But to what end? Anotehr finale for a ventriloquist or opera singer?

“The Bachelorette” (ABC, 9 p.m.) kicks in with a new season, featuring one of the worst former contestants ever – the ever-plastic Emily Maynard, who was chosen by Brad Womack only to have the relationship crumble. Now a couple dozen men who try to make their impression in increasingly gimmicky ways – arriving on skateboard, in a helicopter or in women’s clothing – for a woman who doesn’t seem much behind her fakey smile (and certainly can’t carry on a conversation with her new suitors).

Now that “The Biggest Loser” is gone from Mondays – here’s a two day documentary emphasis “The Weight of the Nation” (HBO, 8 p.m.) which comes brandishing a number of shocking statistics – only a third of the country is not overweight or obese. And there’s surprising details included such as this one: orange juice is as bad as cola and cola is to blame for most of the obsesity. And the weight loss in “The Biggest Loser” is misleading and not helpful either, one doctor says.

A killer returns on the season finale of “Bones” (Fox, 8 p.m.).

The season finale of “Smash” (NBC, 10 p.m.) is actually pretty good.

A wedding caps the season finale of “Mike & Molly” (CBS, 9:30 p.m.).

There are only four left on “Dancing with the Stars” (ABC, 8 p.m.) so tonight’s show is the semi-finals.

The cast of “Mad Men” show up on “Inside the Actors Studio” (Bravo, 7 p.m.).

A thread from last year’s season finale is picked up at the end of two episodes of “How I Met Your Mother” (CBS, 8 p.m.) – who Barney married.

Blair chooses betweek Chuck and Dan on the fifth season finale of “Gossip Girl” (The CW, 8 p.m.). And there’s a first season finale, too for “Hart of Dixie” (The CW, 9 p.m.).

Other season finales come for “Two and a Half Men” (CBS, 9 p.m.).

“Sons of Anarchy” creator Kurt Sutter does research on other gangs on his new series “Outlaw Empires” (Discovery, 10 p.m.).

The musicals of director Henry Koster are featured on Turner Movie Classics: “Stars and Stripes Forever” (8 p.m.), “My Blue Heaven” (9:45 p.m.), “One Hundred Men and a Girl” (11:30 p.m.), “Two Sisters from Boston” (1 a.m.), “The Singing Nun” (3 a.m.) and “The Inspector General” (4:45 a.m.).

In the NBA playoffs it’s 76ers at Celtics (TNT, 7 p.m.) and Lakers at Thunder (TNT, 9:30 p.m.). In the Stanley Cup playoffs it’s game one of Devils at Rangers (NBC Sports, 8 p.m.).

Baseball includes Cubs at Cardinals (ESPN, 7 p.m.).

Daytime Talk

Kelly Ripa: Chris Colfer, Hollie Cavanagh, Jimmy Kimmel. The View: Jenna Ushkowitz, Marc Cherry. The Talk: Martha Stewart, Kim Spradlin, Jennifer Jolly. Ellen DeGeneres: Kate Beckinsale, Taylor Kitsch, Jermaine Paul.

Late Talk

David Letterman: Kelly Ripa, Adam Scott, Tenacious D. Jay Leno: Kourtney, Kim & Khloe Kardashian, Donny Deutsch, Karmin. Jimmy Kimmel: Johnny Depp, Casey Wilson, Silversun Pickups (rerun). Jimmy Fallon: Gorgon Ramsay, Willie Nelson, Jeff Musial. Craig Ferguson: Mila Kunis, Michael Clarke Duncan, Rashida Jones, David Sedaris, Ariel Tweto, the Imagineers. Tavis Smiley: Will Allen, Dev Patel. Carson Daly: Artie Lange, Chely Wright, We Are Augustines. Jon Stewart: Peter Bergen (rerun). Stephen Colbert: Lena Dunham (rerun). Conan O’Brien: Chelsea Handler, Billy Eichner, Doyle & Debbie (rerun). Chelsea Handler: Craig Ferguson, Brody Stevens, Sarah Colonna, Josh Wolf.