R. A. Montgomery, the co-creator, co-author, and publisher of the incredibly successful Choose Your Adventure books, passed away earlier this month. Here’s a look back at a few of the most significant installments in the series.

The Adventures of You on Sugar Cane Island (1975)

While this book isn’t, technically, part of the Choose Your Own Adventure line, it did help kickstart the whole thing. Inspired by the freewheeling bedtime stories he told his daughters, a lawyer named Edward Packard put together an interactive manuscript that allowed the reader to control the flow of the story via a second-person narrative. The innovative book, which featured multiple possible endings, was rejected by nine different publishers before it was finally picked up by a small publishing house owned by Montgomery. It went on to sell 8,000 copies and inspired the duo to create the Choose Your Own Adventure series.

Journey Under the Sea (1979)

Realizing they didn’t have the resources to turn the concept into a huge hit, the duo signed a contract with Bantam, a large publishing company, for six books. Each got started on a different manuscript. Montgomery’s Journey Under the Sea, which led readers on a perilous trip to Atlantis, was the first Choose Your Own Adventure book to hit store shelves. To drum up interest, Bantam gave away copies at book fairs and created teaching guides to go along with it. By 1981, there were four million copies in print. To capitalize on the phenomenon, the company began releasing new installments on a monthly basis, which fans started collecting like baseball cards. A writer for the New York Times called the series as “contagious as chicken pox.”

Inside UFO 54-40 (1982)

This entry was the 12th in the series and featured a bizarre concept involving extraterrestrials. The narrative leads the reader from a Concorde jet onto a UFO where the aliens reveal that they’re searching for a “paradise planet.” None of the possible endings actually lead to the planet, despite the inclusion of an illustration of it in the middle of the book. Fans consider this one a low-point and criticize it for the “false ending.” Even weirder, the book’s cover art features random objects including coins, a crab creature, and an Easter Island statue.

The Race Forever (1983)

This book, number 17 in the series, was about two off-road races. The reader has to choose which one to participate in. After lots of thrills and spills, the narrative leads them over to the alternative race. Then that one leads them back to the first race and on and on and on. The book’s endless story loop means that it’s impossible to actually reach an ending (but it does explain the title).