A perfectly fine history of one of those interesting little niches of early 20th century art which you'd usually be hard-pressed to define to someone who'd never seen it. Dube helps you find an easy answer: Expressionism is basically spiritualized Impressionism. It ain't just the form, baby, or the fleeting grasp at a moment in time--it's all about how the hell it makes you feel and you forcing color and shape to its knees to get you just that.
Although the movement comes across as kind of non-cohesive, you get a lot on some artists (Heckel, Klee, Kandinsky), might discover some lesser known ones (Otto Mueller was my new find) and might want more on some you already know about (Schiele, especially, who gets the shaft in the end).
Overall, a nice survey.