@thomasescritt @pluralistic Adobe Digital Editions is the worst of the worst. It's the most actively user-hostile of all the various DRM schemes. As far as I can tell the guiding philosophy is "Better that a thousand legitimate buyers should be unable to read the books they paid for, than that one pirate should find a way to read a book that they didn't."

Your mileage may, of course, vary, but after my own experiences with ADE, I won't touch anything in that format. No sale.