23 Things to Do Before You Are 11 1/2: A practical step-by-step guide for things to make in your backyard

John Haslam has been working as an illustrator for most of his professional life. John worked in advertising for 10 years and worked on various projects including TV storyboards, to illustrating for all kinds of accounts from Pritt Stick (the Pritt Stick Man was his invention), to comic pages such as Danger Mouse, Disney and Transformers.

Mike Warren is a designer and inventor based in San Francisco. His work combines electronics, woodworking, and reuse. His open-source work is carefully documented to inspire and encourage others to remix his projects and share the results. Warren won The New York Times Innovation Whiteboard in 2012 for his umbrella light (an illumination device retrofitted into the shaft of an umbrella to indicate location to others in the dark) and was the favorite selected by James Dyson. Warren is also the author of a maker book for young adults, 23 Things to Do Before You are 11 1/2, among other titles, and served as the technical editor for the young adult fiction Dewey Mac, Kid Detective. His work has been featured in Popular Science, The New York Times, Wired, BoingBoing, Vsauce, and elsewhere. He is currently a designer for Instructables and Autodesk, where he shares DIY tutorials.