Bob Knetzger, who writes the Toy Inventor's Notebook column for MAKE says:
In Portland yesterday I wandered in to Powell's Books. No, not the big, main Powell's Books, but the small satellite Powell's 2 store across the street. Ever been? It's just the technical book selection and, boy, is it Maker heaven in there!
Computer and electronic books, sure, but a fantastic offering of new and used books and technical manuals hard to find elsewhere: vacuum tube amp design schematics, pyrotechnic journals, every Chilton's ever, machinist's handbooks, scientific theory, statistics, explosives, evolution, kinematics, manufacturing, prototyping, aircraft design, plastics and material science..it goes on and on. Where else can you peruse books like "Anvils in America," " "Moving Heavy Things" or "Keep Your Lathe in Trim?" It passes the acid test by having a vintage copy of my favorite, Ingenious Mechanisms for Designers and Inventors. Oh, yeah, and a nice offering of individual back issues of MAKE!
Skip the crowds in the main store and instead go to Powell's Books 2, pull up a Eames chair and geek out in the lounge with your fave tech books!