It gave no real for reason for ending the series, and it certainly wasn't because of falling ratings. The show continues to be one of the top programs on cable, averaging 5 million viewers in its most recent season. “Monk” is apparently dying of natural causes, with Shalhoub ready to move on to new projects.

In fact, “Monk” is undoubtedly one of the most successful cable series of all time. It established a number of precedents, including the first basic cable comedy to win a major acting Emmy, and it helped usher in the era of the original cable series, clearing a path for USA’s “Psych,” TNT’s “The Closer” and FX’s “Rescue Me.”

“Monk” debuted in 2002, when only a handful of original series dotted the cable landscape. An odd mix of cop caper and “Odd Couple” humor, the show was an immediate hit.

It received strong reviews, based mostly on the performance of veteran character actor Tony Shalhoub, whose portrayal of the fragile, tragedy-scarred detective helped keep the show from veering into a mess of quirks and tics.

“In the actor's skillful hands, Monk emerges not as a solely tragic or comic figure, but as a smart, caring, complex man who is fighting to fully reclaim his body and mind,” wrote Media Life’s Ethan Alter in July 2002.

The show, produced by ABC Studios, also became one of the first, and only, successful cable-to-broadcast crossovers. Later that year, when ABC’s “Dinotopia” bombed on Thursday night, the network brought in reruns of “Monk” to fill in until it had some original content available.

The show performed respectively, and in coming years broadcasters employed a similar strategy with shows like Bravo’s “Queer Eye for the Straight Guy” and ABC Family’s “Kyle XY” to fill empty timeslots during programming gaps.

But it was on cable that “Monk” really stood out. Shalhoub earned the first of three comedic best actor Emmy Awards in 2003, becoming just the second basic cable actor ever to win an acting award, following “The Shield’s” Michael Chiklis, and the first for a comedy.

That helped break a longstanding Academy barrier, and these days nominations for basic cable actors like AMC’s Jon Hamm and FX’s Glenn Close have become commonplace.

That’s partly because of the proliferation of original basic cable series, which again owe a debt to “Monk.”

At its peak in season six, the show averaged 6.1 million total viewers, but it was a solid performer throughout its run, consistently finishing among cable’s top 10 in both viewers and USA’s key demos of adults 18-49 and 25-54.

Perhaps most impressively, that came airing on Friday nights, the least-watched night of the week. It proved that people would make room in their schedules for quality programming, and within three years, it seemed almost every cable network had launched their own signature show.

“Monk” wasn’t without its problems. After two seasons, one of the show’s two leads, Bitty Schram, left in a contract dispute, but producers seamlessly replaced her with Traylor Howard as Monk’s assistant.

But "Monk" will not likely end without closure for the detective and his fans.  There’s speculation that the eighth-season finale finally will reveal who killed Monk’s beloved wife, Trudy, the event that sent the detective into his OCD tailspin.