Harry and Doug investigate when special bookmarks begin to disappear while their class is busy studying poetry and running their own post office.

Miss Mackle's third graders share December holiday traditions--Christmas, Hanukkah, Kwanzaa, Three Kings Day, and Korean New Year--with each other and with Harry's great grandfather, who has just moved to a nursing home.

Harry incorporates his fascination with earwigs into Miss Mackle's class project of acting out a fairy tale in front of the other third graders.

Spurred on by the promise of a mystery prize, Harry and Doug are determined to win the most points on Field Day, but Harry's sneaky tactics annoy their competition, making the two boys targets for revenge.

"Best friends Harry and Doug must find their teacher's missing diamond in time for the class talent show."--

Horrible Harry sets out to discover who Miss Mackle is going to marry, and he takes some risky moves to be the first one to know.

Working on a dragon project in Room 3B leads to a war between two good friends--Harry and Song Lee.

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.

Miss Mackle is getting married! But she didn’t invite any of her students to the wedding. The kids don’t understand it: a wedding is a time for families to be together, and they are Miss Mackle’s Room 3B family—which is especially important because her father is in the military overseas, and he won’t be home for the wedding. So Harry comes up with a plan to sneak his pals into the wedding ceremony and hide in the back. It seems like the...

When his best friend's family plans to move away, Herbie Jones does what he can to cope with the change.