Our subscriber base has grown so much since we first started nine years ago, that most of you have missed all our earliest recommendations. The best of these are still valid and useful, so we’re trying out something new — Retro Recomendo. Once every 6 weeks, we’ll send out a throwback issue of evergreen recommendations focused on one theme from the past 9 years.

Quick research explainers

Two Minute Papers is a YouTube channel featuring short videos (sometimes 5 minutes long) created by a professor who reviews new research papers in visual programming, artificial intelligence, machine learning, computer graphics, simulations, and other state-of-the-art computer science. He explains the research’s significance, while running very cool graphics demo-ing the results. I find it a painless way to keep up in this fast moving field. — KK

Understanding physics

Isaac Asimov’s 768-page Understanding Physics clearly explains the principles of motion, sound, heat, light, magnetism, and electricity in a historical context. It gave me a better understanding of physics than four years of mechanical engineering school, and was actually fun to read. — MF

Collaborate with scientists

NASA has a page dedicated to their Citizen Science Projects where you can volunteer to help make scientific discoveries, like mapping bird diversity, cloud gazing, tracing patches of kelp, or identifying celestial objects in search of Planet Nine. Currently, there are 30 projects open to anyone in the world, and most can be done with just a cellphone or laptop. — CD

Best geology overview

Often science documentaries these days are fluffy with wiz-bang graphics, slick re-enactments, endless repetitions, and fancy hosts, but Doug’s Geology Journal, a series on Amazon Prime, has none of those. Doug is a regular-guy geologist who draws his own graphics with pencil, and carries his own camera as he trudges across the landscape, giving the big picture of what has happened to shape the land, and how that shapes the culture on it. He gives you the right level of details, at the exact place on the land, which makes the big picture visible. He’s my favorite geology teacher. — KK

Retro anatomy book

I have a small collection of mid-century science books for young adults, and one of my favorites is The Human Body: What It Is and How It Works. Published in 1959, this beautifully illustrated book describes how our muscular, reproductive, digestive, endocrine, respiratory, skeletal, nervous, and circulatory systems work in simple English. Out of print but inexpensive used copies are easily found online. — MF

An app to teach you about the fourth dimension

This iPhone/iPad app does just one thing — it gives you a feel for the fourth dimension by moving from 0 dimensions to 4. I’ve had this jewel of an app on my phone for years and still open it from time to time. It’s a great companion to Flatland. — MF

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In 1952, AI pioneer Marvin Minsky created the “ultimate machine.” la machine is a re-invention of this delightfully pointless device with a stunning design and hundreds of unique interactions (with sounds!). 100% open-source too.

Springsteen released an album of demos? Bon Iver nearly quit before his best album? Dylan lived in a frat house? Subscribe to The Listening List for weekly song recs with the stories and context you’ve never heard.

Recomendo is an authentic, hand-crafted, human-written weekly newsletter that is free, but not cheap. Consider supporting our work with a paid option, now at the low price of $45 per year. Paid subs enable us to keep making it free for others. Recomendo is published by Cool Tools Lab, a small company of three people. We also run the Cool Tools website, a YouTube channel and podcast, and other newsletters, including Gar’s Tips & Tools, Nomadico, What’s in my NOW?, Tools for Possibilities, Books That Belong On Paper and Book Freak.

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