Professor Gordon agrees with, and expands on, the assertion that "Econ 1 (or Econ 101) is all you really need". (I agree, too.)
He recommends The Economic Way of Thinking, which I also like. And I'll plug Trade-Offs: An Introduction to Economic Reasoning and Social Issues, Second Edition. (It's narrower in scope, but the benefit is a tight focus on a really important idea in economics.
Related, by Paul Rubin: "We Must Teach College Students Basic Economics".