For several years now, summer has belonged to cable. The junior networks have gained audience and showcased superior programming, while the networks have relied on reality fodder and gimmicky talent contests. As a result, the cumulative cable audience has been larger than the networks’ share for at least the past five summers. If you offer quality, people will come.

Now in its fifth season, the offbeat police comedy “Monk” (8 p.m., USA) has been part of this smart cable revolution.

“Monk” opens its fifth season with a great episode and a wonderful cameo appearance. As the episode begins, Adrian Monk (Emmy-winner Tony Shalhoub) appears to be on the verge of a psychological and personal breakthrough. He’s about to go on vacation alone – his first solo trip since the murder of his beloved wife.

Feeling frisky, he’s happy to hear that Hollywood is making a movie about a recent case solved by himself and the San Francisco police. The arrival of a movie crew and actors who shadow the real players is a great touch, reminiscent of the great “Seinfeld” episode in which the “real” sitcom stars watched the “fake” sitcom with just-not-quite facsimiles of themselves.

Unfortunately for Monk, the actor (Stanley Tucci) playing him is a stickler for method and motivation and wants to get inside his subject’s head. It’s a joy to see Tucci “become” Monk. The two actors are natural together, having appeared in the wonderful, bittersweet drama “Big Night” in 1996, where they both play co-owners and chefs in a failing Jersey Shore restaurant. If you haven’t seen this little gem, go rent it. Now.

The episode also makes some comedic points about the psychological dynamics of acting. Some of the insights that Monk experiences while coaching his alter ego seem to transcend any progress he’s made with his therapist. But whether this experience is positive or destructive – for either man – remains to be seen.

¢ “Greatest Moments: Dolly Parton” (7 p.m., CMT) follows the career of the country star from her earliest appearances on “The Porter Waggoner Show” and appearances at county fairs in Tennessee. Along the way, critics, fans and fellow musicians discuss her career choices and musical evolution.

Tonight’s other highlights

¢ A suspect dies in custody on “NCIS” (7 p.m., CBS).

¢ On two episodes of “24” (Fox), Jack returns to the president’s good graces (7 p.m.) and encounters an old mentor who went bad (8 p.m.).

¢ The squad tries to plant an embassy bug on “The Unit” (8 p.m., CBS).

¢ Danny bonds with a mystery woman seen in family photos on “Las Vegas” (8 p.m., NBC).

¢ Kyle’s insomnia won’t go away on “Kyle XY” (8 p.m., ABC).

¢ The voices of John Goodman and Billy Crystal animate the 2001 cartoon “Monsters Inc.” (8 p.m., Disney).

¢ A bombing reveals buried information of a personal nature on “Numb3rs” (9 p.m., CBS).

¢ McCoy must deal with the devil to save a young hostage on “Law & Order” (9 p.m., NBC).