Someone has been leaving creepy notes in lockers, notebooks, and knapsacks all over school, with messages like "I Know What You Did Last Week." Students are getting really annoyed. And the notes all appear to be written by one person-Lizzie McGuire! But who would want to frame Lizzie for such a totally bizarro prank? Time for Lizzie to track down the guilty party before she's exiled to Loser-ville forever!

Summer vacation is here, and Lizzie’s less than thrilled. Why? Because her parents were less than thrilled with her report card-so they’re sending her to science camp. Ugh! Luckily, her best friend, Gordo, is going to Camp Bunsen Burner, too-but not because his science grades are weak. He’s actually excited about going. Gordo even enters the camp’s Best Invention competition. And that’s the reason he needs Lizzie’s sleuthing help.... Someone has stolen Gordo’s entry-a brilliant formula for glow-in-the dark mosquito repellent. Is it Larry Tudgeman? Or the suspicious (but very cute! ) Camp counselor? Or could it be the chemistry teacher himself? Lizzie promises to help Gordo find his formula - and, in return, maybe he’ll find a way to get her outie!

In a (failed) effort to be cool in school, Lizzie hurts the feelings of major she-geek Audrey Albright. It's a total mistake and Lizzie wants to apologize-but Audrey's disappeared. She was last seen in the girls' room, crying. Then she doesn't come to school for days. With Gordo and Miranda in tow, Lizzie follows a trail of clues to a science-fiction convention, where Larry Tudgeman becomes their guide through the underworld of geekdom. But is Lizzie really ready to go where no cool kid (like ever!) has gone before?

Lizzie offers to sign on for some truly grueling undercover work. Her crush-boy, Ethan Craft, has entered this year's Mr. Teen Hottie pageant-and he's in major trouble. Someone is trying to wreck his chances of winning the top spot! Of course, to ferret out the fink, Lizzie will have to pose as Ethan's girlfriend. It's a tough job but somebody's gotta do it, right? (Added bonus: it's sure to seriously annoy Lizzie's archrival-Kate Sanders, Queen of Mean!)

In the Doghouse (Lizzie McGuire Mystery #5): To raise money for an animal shelter, Lizzie starts her own dog-walking and dog-sitting business with her two best friends, Miranda and Gordo. The idea is such a good one that cheerleaders Kate and Claire are seriously jealous-since their own lame pom-pom fundraiser is a total failure. Then someone lets the dogs out of the McGuires' backyard, and Lizzie is really in the doghouse. She not only has to track down the missing dogs, but she's also got to track down the guilty party before he or she strikes again! Could it be her jealous rivals? Her toxic little brother's idea of a prank? Or what about those two neighbors who wouldn't stop complaining about the barking? Time for snoop dog McGuire to sniff out the truth of this doggone mystery!

April showers bring…muddy footprints! Spring It On! (Lizzie McGuire Mystery #7): Spring has sprung at Hillridge Junior High, and that brings two things: the big Spring Fling dance and spring showers. While the unending rain depresses Lizzie, Miranda is totally psyched. Her theme for this year's Spring Fling dance (Flower Power!) has been chosen over a ton of other student ideas. Now Miranda is in charge of the whole thing-and she's drafted Lizzie to help. Unfortunately, disasters begin to "spring" up as Miranda and Lizzie prepare the gym for the dance, and Lizzie suspects foul play. Can she track down the spring sneak before her best friend's big