I love my job, but something tells me How 2.0 would have been even more fun to run 40 years ago. Witness this 1964 PopSci article—with actual schematics—on building your own"ruby ray" laser. The best part is the sell: "The incredible ruby ray is one of the hottest scientific discoveries of the decade but practical uses are still scarce. Here's your chance to join the search." There's some advice we don't see enough of today: "Here, build some experiemental high-power stuff in your basement and let us know if you find something interesting to do with it."
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.