Mark Alexander is a self-taught programmer and writer. He started using BASIC on an old ZX81 and progressed through the years using other languages and learning the tools of the programming trade until he discovered GameMaker in 2006. At that point, he fell in love with the software and now dedicates his time to making games and writing articles on using the program and on game design in general.

Mark currently documents products for YoYo Games (who makes and sells GameMaker: Studio) and also has his own small software company, Nocturne Games, which specializes in small, family-friendly, and quirky games for all platforms.

Mark was the technical editor of GameMaker: Studio For Dummies, For Dummies as well as Learning GML from the Game Maker book series.

John M. Walker, PE is a licensed professional engineer in industrial engineering and is currently a licensed full-time teacher in computer science and information technology at Gresham High School near Portland, OR. He has been teaching full time for the last 15 years for High School and Regional Professional Higher Ed conferences.

John worked for more than 20 years as an information technology manager for high technology firms dealing with systems administration and networking architecture and engineering. His favorite designation was Director of Technology for the Portland Trail Blazers, while designing and constructing the Moda Center.