Niles was one of the creators of the Dragonlance world and the author of the first three Forgotten Realms novels, the Star Frontiers space opera setting and the Top Secret S/I espionage role-playing game.

Niles was born in Brookfield, Wisconsin, a suburb of Milwaukee, and his family moved to Nashotah, a small town to the north, when he was twelve years old.

[1] After graduation, Niles began teaching Speech and English at Clinton High School, about 30 miles away from Lake Geneva, Wisconsin.

I kept pestering my boss, Al Hammack, for a design assignment, and finally he gave me an old brief for a novice-level module, Cult of the Reptile God, and told me to write it.

[3] Niles worked on the Battlesystem Supplement, Star Frontiers modules SF4 Mission to Alcazzar and SFKH1 Dramune Run, Indiana Jones module IJ2 Raiders of the Lost Ark, the World War II Game, the Sirocco Strategy Game (with Zeb Cook), and the Endless Quest books EQ #26 Tarzan and the Well of Slaves and Super EQ #3 Escape From Castle Quarras for TSR.

[1] Tracy Hickman had gotten Harold Johnson, Jeff Grubb, Carl Smith, and Larry Elmore in on the idea of Dragonlance before Margaret Weis and Niles joined them.

[citation needed] Niles and Paul Lidberg designed the board game A Line in the Sand (1991), which focused on the Gulf War between the US and Iraq; it was one of the projects originating from TSR West, and was published the day the US started bombing because Flint Dille convinced the company president to move quickly.

Niles is one of the most prolific Dragonlance authors, and in addition to Wizard's Conclave, his Dragonlance titles include The Icewall Trilogy (The Messenger, The Golden Orb, Winterheim), Emperor of Ansalon, The Dragons, The Puppet King, Fistandantilus Reborn, Flint the King (with Mary Kirchoff), and The Last Thane.

[5] Niles has designed dozens of games for TSR, Inc. and SPI, including award-winning boardgames based on Tom Clancy's novels The Hunt for Red October and Red Storm Rising, and has also created numerous historical military boardgames, including the massive games European Theatre of Operations and Pacific Theatre of Operations.