I borrowed this book from a friend in 4th or 5th grade, read it, and loved it. Many years later, I bought my own copy of this book and its sequels, bound together in a book club omnibus. I still liked them.

The premise of the first book is that a group of present-day college students are playing a Dungeons and Dragons-like game, and through the sinister machinations of a college professor acting as the Game Master, they are transported into the world of the game. You can see how the fantasy of entering a fantasy world appealed to a 5th grade me. Despite this, the book and its sequels are still very good.

After the first book, the fact that the characters are from a present-day setting is nearly forgotten, aside from the fact that they form a small community with advanced architecture and engineering, and invent gunpowder. Some of the characters, like James-Michael Finnigan, a cripple who enters the body of a muscular dwarf, embrace their game-character-selves. Others, like Ricetti, expunge their fantasy personae and remain their 20th century selves. That in itself is an intriguing subject. It's also very fascinating to watch the characters integrate themselves into the fantasy society, their futuristic perspectives and practices changing that society in many interesting ways. Eventually, the characters take up a crusade against the powerful slavery trade, and make themselves some very powerful enemies.

The target audience is very obviously D&D players, but I still think this is a good read.