Last summer, USA Network's "Monk," a comedy-drama series about a San Francisco detective with obsessive-compulsive disorder, arrived from out of nowhere, a totally unexpected treat.

As it returns for a sophomore season Friday night at 10, "Monk" remains delightful - but it's changed a little.

Some of the changes, especially a more recognizable cadre of guest stars, reflect the show's well-deserved success. Others are slight variances from established character traits, and are less welcome.

Overall, though, "Monk" remains one of the few bright lights in an otherwise dim summer TV lineup.

Last year, "Monk" built its reputation on the strength of creator David Hoberman's unusual series concept, Tony Shalhoub's flawless leading performance and a small but invaluable supporting cast, notably Bitty Schram as Sharona, Monk's gal Friday.

Tonight's pilot also features Andrew McCarthy, as the prime suspect; Rosalind Chao from "St. Elsewhere," as a school official, and David Rasche of "Sledge Hammer!," as a coach and bully.

The central mystery - crucial to this show's success - is clever, is resolved nicely and allows Shalhoub, as Monk, nice moments along the way.

What has been done to Monk's character this year, though, is a little troubling. They've made it easier for him to move about in the world, and suggest it takes more to set him off.

In Friday's opener, Monk goes undercover as a substitute teacher, a scenario that provides the hour's best scene as he introduces himself to the class by writing his name on the board. He writes it so slowly and obsessively, and corrects it so often to make the penmanship just so, that the scene's mirth just builds and builds. Shalhoub milks it for every ounce of humor.

Then he's hit from behind with an eraser. The chalk dust and sudden impact all but paralyze him. It's a shift from the comic to the serious that "Monk" does so well - but this year, his neuroses seem more manageable and less painful to him. The old Monk probably wouldn't have even held the chalk without wearing gloves.

There's enough of that old "Monk," shown leveling the coffee in carafes and being preoccupied by a single unbroken windowpane in an otherwise destroyed house, to keep things honest.

The writers should avoid, however, making Monk's road to recovery too swift or easy. On this show, just as the humor leavens the tragedy, the tragedy strengthens the humor.

"Monk" needs both.

What it doesn't need, by the way, is a new theme song. But it gets one this season, courtesy of a bouncy new tune by Randy Newman. I'm as big a Newman fan as you can get - but the show's original jazz-guitar theme, still heard as the closing credits roll, was perfect for the tone of "Monk."

Sometimes, change isn't an improvement. It's just a change.

Originally published on June 17, 2003