We've started a new exercise at work where we host a "Design Potluck" every Monday where anyone in the company is welcome to bring pieces of design to a group where we discuss what we think is successful or unsuccessful, and how it could relate to our company. Aside from keeping us current with design from the real world, it's a great opportunity for my coworkers from non-design backgrounds to expand their design vocabulary.
After this week's meeting I got a number of people expressing interest in practical design theory and history. I credit a large part of my working knowledge to the books I read in my formative years leading up to college and graduation. In addition to reading design books I had heard about on various blogs, I benefitted greatly from a formal art education that included classes about art theory and history from antiquity. First assembled for other members of DoSomething design and product teams, I put together a page of highly influential books that informed my design education. Loosely organized in order of most impactful per category, I've copied the list below. All Amazon links are Smile links benefitting the Heaven Can Wait Animal Sanctuary.