When you were a kid, did you wish you were in Mrs. Jewls’s class on the 30th floor? Wonder what Mushroom Surprise really tasted like? Ponder getting a potato tattoo?

If so, you weren’t alone. Every child who read Louis Sachar’s Wayside School surely thought Bebe Gunn, Benjamin Nushmutt, and the Three Erics were having way more fun at school than they were.

But while the outlandish stories may be straight from Sachar’s imaginative mind, the kids were totally based in reality. When he was at Berkeley in the ‘70s, Sachar took a job as a teacher’s aide in exchange for three college credits. In addition to helping out in a second and third grade class at Hillside Elementary School, he also monitored the kids during the lunchtime recess, where he was known as Louis the Yard Teacher.

“It became my favorite college class, and a life-changing experience,” he said.

When he started writing the first Wayside book in 1976, he based all of the characters on the kids he got to know at Hillside—and there’s probably a nugget of truth in each of their personalities, since Sachar says his writing process was to “picture [the kids] in my head and describe them. The illustrator then drew the pictures, which looked nothing like the real kids I knew.” His favorite kid from Wayside, by the way, is Todd—the boy who always ends up getting sent home on the noon bus for bad behavior. The first Wayside character he created was Mrs. Gorf.

The eclectic group at Wayside aren’t the only characters Sachar based on real-life people. His wife, Carla, was a counselor at an elementary school—just like her namesake in There’s a Boy in the Girls’ Bathroom. The Warden from Holes was based on a friend of his who plays bridge, and Louis the Yard Teacher in the Wayside books was, of course, based on himself.