... the Zentrum Paul Klee made available online almost all 3,900 pages of Klee’s personal notebooks, which he used as the source for his Bauhaus teaching between 1921 and 1931. If you can’t read German, his extensively detailed textual theorizing on the mechanics of art (especially the use of color, with which he struggled before returning from a 1914 trip to Tunisia declaring, “Color and I are one. I am a painter”) may not immediately resonate with you. But his copious illustrations of all these observations and principles, in their vividness, clarity, and reflection of a truly active mind, can still captivate anybody  — just as his paintings do.