Calibre does not remove DRM as a built in feature but there are plugins available that do it. DRM is bound to lose on books. One reason is the analog hole, sam

Calibre does not remove DRM as a built in feature but there are plugins available that do it. DRM is bound to lose on books. One reason is the analog hole, same as with music. A dedicated hobbyist with a scanner and OCR could easily produce unencumbered e-books even if DRM were perfect. Also, the bits in an e-book are always going to be easy to pirate just because there are so few of them. A book weighs in around a half a megabyte of uncompressed text.