Ever wonder how people found anything out before the internet? Or how those people without smart phones are able to operate?
Answer: Pocket Ref, Fourth Edition
It might not fit in your skinny jeans, but almost. This 864-page mini-tome covers everything from First Aid (how to treat a sucking chest wound, anyone?) to Airline Toll Free numbers, to Wood Gluing Characteristics, to Cloud Types (how to identify a stratocummulous) to Element Properties. I highly recommend it as a desktop companion for all the charts, tables, and diagrams that aren’t always easy to Google. And, its kind of fun to read too (in a highly MIT-nerd kind of way).