Bill Gates' mobile library. Ian Allen.

I travel everywhere with these bags—a hodgepodge of books I've read and ones I'm working my way through. (Some have been around the world more than once, but I'm determined to get to them.) I read while traveling, waiting for meetings, in the evening, and especially on vacation. As you can see, I'm still pretty much an old-school print guy, because I like to jot notes in the margins, but I assume I'll move over to ebooks when annotation features get better.

1 // Feynman's Tips on Physics – A short companion book to Richard Feynman's classic Lectures on Physics. Always worthwhile to return to the feet of the master.

2 // The Cartoon Introduction to Statistics – Bought this to use with one of my kids. Helpful in explaining a complicated subject to a teenager.

3 // Super Sad True Love Story: A Novel – I don't read a lot of fiction, but I thought this was an interesting study of the moral implications of technology. Will tech­nology contribute to everyone's well-being or just make people more narcissistic?

4 // The Great Courses (DVD) – I left college early, but I'm probably the world's biggest consumer of academic courses online and on disc. Lately I've been enjoying Understanding the Secrets of Human Perception and Oceanography: Exploring Earth's Final Wilderness. Neil deGrasse Tyson's lectures on astro­physics, My Favorite Universe, are also really compelling.

5 // The World Until Yesterday: What Can We Learn From Traditional Societies? – I'm a big Jared Diamond fan; I invited people to read this with me last summer.

6 // Tap Dancing to Work: Warren Buffet on Practically Everything – Any compilation of Warren Buffett's wisdom should be kept close at all times. Financial journalist Carol Loomis gathers some of his best here.

7 // The Path Between the Seas: The Creation of the Panama Canal – I read this to prepare for a family vacation to Panama. It's pure McCullough: epic drama, political intrigue, heartbreaking defeats, and eventual triumph.

8 // The Better Angels of Our Nature: Why Violence Has Declined – One of the most important books I've read. Steven Pinker demonstrates how the world evolved to be far less violent. Counterintuitive, if you watch the news, but true.