Michael Hartl is author of Ruby on Rails Tutorial. ^[0]

Hartl created Tau Day and The Tau Manifesto, which have inspired an international movement dedicated to the proposition that “pi is wrong.”

He is also founder of Softcover, a publishing system and sales platform for technical authors.

Michael is a graduate of Harvard University and has Ph.D. in Physics from California Institute of Technology - Caltech, where he studied black hole dynamics and was an award-winning instructor in theoretical and computational physics.

He's an alumnus of Y Combinator.

^[2]

In 2016 and 2017, Hartl was at work on a series of introductory books for full-stack programming under the name Learn Enough to be Dangerous, [6] such as *Learn Enough Command Line to be Dangerous.

[7]* ** Like his Rails tutorial, these books were available free on his website, LearnEnough.com, with additional products available (such as videos) for a premium.