The boys are growing up. That's sort of the overriding theme of Relient K's fourth album, mixing their version of Christian pop-punk with maturing themes about life, love, and faith. The band whose last albums were The Anatomy of the Tongue in Cheek (with songs devoted to Mr. Ed, another about the "Sadie Hawkins Dance," and a third called "Maybe It's Mabeline") and Two Lefts Don't Make a Right . . . But Three Do (with "Mood Rings," a song that suggested "let's get emotional girls to all wear mood rings/so that we can be tipped off to when they're ticked off") decided to change gears a bit on this one.

Their lyrics still retain the quick wit and occasional flashes of biting sarcasm that accompanied their earlier songs, but they're not in high school any more - or in their garage, either. The production values have improved and it affords them the opportunity to add depth to the musical arrangements. But while they offer up a few more mellow, thoughtful tunes, they also still manage to deliver a fair amount of their trademark pop-punk attitude on "The One I'm Waiting For" and "I So Hate Consequences."

Their earlier albums were characterized by a blazing jumble of guitars and a smart-aleck sensibility, and mmhmm don't so much reject that history as it does build upon it. My Girlfriend's Ex-Boyfriend is a declaration of adoration but also a sidewise slap at a predecessor:

If it wasn't for him/I would still be searching/If it wasn't for him/I wouldn't know my best friend/If it wasn't for him/He would be able to see that/If it wasn't for him/He'd be as happy as me.

When she and I settle down you can bet/That he is going to settle for less/He's someone I would hate to be/I got the girl, and he's left with just the memory.

Their rambunctious combination of frantic music and intricate lyrics continues on "The Only Thing Worse Than Beating a Dead Horse is Betting On One," and they offer up an infectious pop-punk fusion on "High of 75." "Which To Bury, Us or the Hatchet" demonstrates an honest depth of emotion, while "More Than Useless" and "Who I Am Hates Who I've Been" explore the meaning of faith. It's a maturing, evolving Relient K playing on mmhmm, and it's a fun, rollicking ride.