Michael Hartl


In 2015, the Rails Tutorial mutated into a startup when I cofounded Learn Enough, an education company dedicated to teaching computer programming and related subjects. Learn Enough includes books, videos, and online courses covering subjects such as the Unix command line, text editors, version control, HTML, CSS & Layout, JavaScript, and Ruby.

I’m also the founder of Tau Day and author of The Tau Manifesto, which argues that the true circle constant is the ratio of a circle’s circumference to its radius, not to its diameter. Conceived principally as a social hack, Tau Day and the number
τ=C/r have become an international phenomenon, striking a chord (sometimes literally) with math geeks all over the world, while inspiring a Vi Hart video, subverting the traditional circle constant at the Khan Academy, and even influencing the timing of MIT admissions announcements.

Other interests include reading old books, languages, physical fitness, and martial arts (including Krav Maga Level 5, a “black belt in self-defense”).