Harry's in love, and his best friend, Doug, is disgusted -- Harry won't even throw snowballs at girls anymore. Will Harry ever go back to being his horrible self?"Kline captures perfectly the crowd scenes and private moments in the classroom."-- Booklist

Another fun mystery starring Horrible Harry, and this time he's calling the shots! Harry has always loved solving mysteries, and now his friends in Room 3B have learned to love it, too. So Harry challenges them to figure out what he has hidden in his giant, old suitcase. Led by a very determined Mary, the kids take turns solving clues and piecing the mystery together. Their hunt leads them from the classroom to the library, and even to Harry's grandfather's nursing home. Will they be able to solve Harry's mystery? Or will things go horribly wrong for the novice detectives?

Doug discovers that though being Harry's best friend in Miss Mackle's second grade class isn't always easy, as Harry likes to do horrible things, it is often a lot of fun.

It’s a horrible day for Harry: a classmate is calling him names; his library book is overdue; he’s last in line for a turn to be the Room 3B VIP. Worst of all, it’s cold and icy outside again, which means no outdoor recess. It’s all too much for Harry—he starts to go cuckoo! Fortunately, there is a solution to Harry’s problems . . . but it comes from a very unexpected source.

Harry leads a mission to place cobwebs all over school, shows the class how to make green slime, and stages a "deadly skit" that has everyone on the edge of their seats.

After four days in a row of indoor recess, Miss Mackle's students are bored-until Harry decides to solve the biggest mystery ever in Room 3B! There's a locked closet in the classroom that's been sealed off for years, and he wants to know what's inside. So Harry drafts Doug, Song Lee, and the rest of the class to help him investigate. Their search reveals many surprises-from a hidden trapdoor to...eyeballs! What secret treasures does the closet hold? Is it something more horrible than even Harry can imagine?

An insightful addition to the Horrible Harry series about appreciating and preserving the environment in your own backyard. Doug thought he knew everything about his best friend, Harry . . . until he discovers that Harry has a secret hideout in the woods just outside of South School. Unfortunately, Harry can’t keep his hideout a secret much longer, because the land is going to be sold and turned into a big apartment building—unless he and the rest of the kids in Room 3B can save it. Harry has the idea to turn the lot into a nature center, and his friends want to help after he shows them the beautiful wildflowers, yellow spotted salamanders, and slimy tadpoles. But can Harry persuade the school board to agree, too? Or will his horrible fear come true: losing his hideout forever? Praise for the Horrible Harry series: "Room 2B is every child's dream...This is one school story which rates an A+."—School Library Journal (Horrible Harry and the Green Slime) "Another perfect chapter book for transitional readers."—School Library Journal (Horrible Harry and the Drop of Doom) "Kline has an exceptional talent for capturing the language, humor, and group dynamics of a primary grade classroom... An attractive read for children just beginning to tackle novel length fiction."—School Library Journal (Song Lee in Room 2B)