Free reading: Guggenheim posts Klee, Kandinsky, 60+ art books online
In keeping with its educational mission, the Guggenheim Museum has posted 65 art catalogues online for free reading. These are books created and published in connection with modern and contemporary art exhibits at the Guggenheim over the past decades, including works about Alexander Calder, Evard Munch, Vasily Kandinsky, Mark Rothko, Eva Hesse, Josef Albers, Francis Picabia, Paul Klee, Francis Bacon and many others. It also includes the catalogues of group shows and themed exhibits.
The Open Culture website (where I learned about the catalogues) has a helpful short introduction to reading the Guggenheim books online. (All you need is a web browser.)
But Open Culture also points out that you can download the catalogues, too, for offline and mobile reading. The downloadable catalogues, in multiple formats including PDF, EPUB, Kindle and text iterations, are hosted by the Internet Archive.
Please note these are curatorial and scholarly essays, not simplified texts, so your reading pleasure may vary from catalogue to catalogue. But if you have any interested in modern art, it's worth your time to browse these works.