Leary's Tommy Gavin, the haunted New York firefighter of Rescue Me, isn't played strictly for laughs. Quite the contrary: This series, which begins its sixth season tonight at 10 ET, is one of the best at flipping instantly from laugh-out-loud funny to drop-the-jaw intensely dramatic. From Leary, a veteran standup comic, the hilarious one-liners, and the impeccable timing with which he delivers them, are no surprise. But once again, this man proves that he can ACT.

His comic reactions, when he's quietly absorbing the verbal abuse of his daughters while trying to lecture them, or dealing with the unsympathetic ribbing from his fellow firefighters, are priceless. Leary is as funny when he's listening as when he's speaking, which is the sign of a true comic actor, not just a true comic. And when he's called upon to do something that's dead serious -- dive into a heated argument, say, or reach for another liquor bottle -- he does it with conviction and assurance.

This two-part final season for Rescue Me, split into halves and timed to conclude on the 10th anniversary of 9/11 next year, means we're heading to the end of Tommy's story -- with no assurances whatsoever that it will be a happy ending. But by this point, we're so invested in all of this show's characters that, whatever happens, we expect the ending to be both memorable and moving.

And there's one other strong argument for watching Rescue Me: It gives meatier roles, and more dynamic scenes, to its leading actresses than almost any series on television. Callie Thorne, as Tommy's demanding, high-maintenance mistress, is cracklingly vibrant in every scene, and Andrea Roth, as Tommy's ex-wife, is capable of dismantling or dismissing him instantly, sometimes without saying a word.

The male co-stars, too, show the same strong assurance, going for the laughs (and getting them) in some scenes, and playing it straight in others, as the script demands.

And this year, more than ever, the young actresses playing Tommy's coming-of-age daughters -- Olivia Crocicchia as Kate and Natalie Distler as Colleen, whose growing alcoholism becomes a major plot concern this season -- get a lot to do, and do it impressively.

Leary and series co-creator Peter Tolan have made Rescue Me one of TV's most reliable pleasures, and treasures, since 2004. The first four episodes of this new season suggest their personal fires have not ebbed at all -- so prepare, as Tommy does in the opening minutes, for a very bumpy and unforgettable ride.

Premiering tonight at 11 ET after Rescue Me is Louie, the new series starring another standup comic, Louis C.K. This is such a change from HBO's Lucky Louie -- such a welcome change -- I can't tell you. But I'll try.

Louie is a single-camera series, set and shot in New York, on which Louis C.K. is carrying most of the weight: writer, director, editor, executive producer, star. He's drawn from two of TV's all-time comedies, Seinfeld and Curb Your Enthusiasm, for inspiration, tone and structure, but he's also added something of his own -- something which makes Louie his own.

The obvious debts -- doing stand-up comedy routines to complement the situation comedy part of the show, a la Jerry Seinfeld, and complaining to people about their boorish or bad behavior, a la Larry David -- are done well. The solo routines, especially, carry a lot of punch. They're more extended than the ones on Seinfeld, and, almost without exception, a lot more razor-edged.

But the sitcom scenes, too, resonate with truth, and an edge, that may have you reflecting on them long after the TV set is off.

When the TV version of Louie (who, like the "real" version, is divorced and raising two young girls) goes out on a date, his observations are so full of frustration and resentment, yet so funny and true, you'll laugh almost despite yourself. And in this scene and others, just when you think you know where things are going, C.K. adds a twist, or a surreal touch, that leaves you surprised. And smiling.

Neither Seinfeld nor David, in their TV incarnations, spent much time with kids, who are one of the main obsessions and reliable joys of the TV Louie.

The two girls, and the paces through which they put their father, is one of the elements that make Louie its own. Even a standup routine about volunteering as a monitor in the school lunchroom is unique, it seems, to C.K.'s perspective: Who else does that?

But it works. Louis C.K., by taking firm control of his new TV series, has converted me into a fan.