A story 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?

Horrible Harry says goodbye in the 30th anniversary finale of a beloved series! The last day of third grade is approaching fast, but a farewell to Room 3B isn't the only goodbye Doug has to say this year. Song Lee and Mary are busy preparing an end-of-year present for their favorite teacher, Mrs. Flaubert, but their excitement can't distract Doug from Harry's suspicious silence. When Harry finally admits that his family is moving to a whole other town, Doug can't believe his ears. How will he survive fourth grade without his best friend?! But Harry has a more pressing question: who's that moving in to the empty house across the street from him? And what could these new neighbors mean for their friendship?

Horrible Harry is at it again in a rollicking story of Field Day adventures, mishaps...and revenge! It’s one of the best days at South School: Field Day! That means bean bag tosses, relay races, and tug of war. When Mr. Deltoid announces students will pair up to compete for a mystery prize, Harry and Doug are determined to win. But at what cost? Harry's sneaky tactics leave Sid and Mary grumbling. They even claim he’s cheating. Harry insists he's playing fair and square. Doug doesn’t know what to think! He must prove his best friend is innocent before his classmates seek Field Day revenge. Can they win and play by the rules, or will the highlight of the year be a horrible disaster?

Mary is always neat and organized, while Harry is horribly messy. But even Mary’s carefully planned schedule can’t help when things go wrong at her own birthday party. The party is supposed to start with the kids from Room 3B taking an exciting train ride, but when their train is delayed not one . . . not two . . . but three times, Mary’s plan is completely ruined! She thinks the only thing that can make her feel better is cup after cup of sugary Island Punch—even after her mom tells her to stop. But what Mary doesn’t know is that Harry has his own wacky ideas for saving Mary’s big day. Can the kids still have fun even when nothing’s going the way it’s supposed to, or will this be the most horrible birthday ever?

Harry loves creepy-crawly things. But there’s one creepy-crawly thing that even he can’t stand: head lice! So it’s a terrible day when Harry’s friend Doug discovers lice in his hair. To make matters worse, Mary makes fun of Doug for being dirty and convinces the rest of the kids in Room 3B that they can’t go near him. She claims that everything he touches is infested with lice—even the mac and cheese at lunchtime! Doug wants to run away to Siberia instead of facing his classmates South School. But Harry and Song Lee stand by him and declare battle on the bugs. Will Harry defeat the hated lice, or will Doug have to live with these horrible bugs forever?

"When his best friend Doug discovers his top-secret hideout, Harry enlists his friends' help to save it from being developed into an apartment building"--

List of charter members of the society: v. 1, p. 98-99.