Recent 21cm HI observations with the Green Bank Telescope have contributed to a major revision of our understanding of the transition between the Galaxy's disk and halo. In the inner Galaxy we now see a population of discrete clouds extending far above the plane which follow galactic rotation but whose origin is otherwise obscure. Ironically, they are the best known examples of diffuse interstellar clouds in any environment, and their study is likely to influence many areas of astrophysics. In the outer Galaxy we see further evidence that the Milky Way is still accreting material. The Galaxy must have a very extensive diffuse halo which affects clouds as they pass nearby.