Even the slightest acquaintance with discussion swirling around e-books will likely trip you over the idea of DRM, or Digital Rights Management. Publishers like it because it means recompense for work. Readers range from acceptance to active hostility, when DRM encoding means an e-book usefulness/ability to be read may be severely limited (eg. to few file types, or a single e-reader device etc). Naomi Novik, author of the Temeraire series, participated in an interesting discussion on DRM: Will E-book Anti-Piracy Technology Hurt Readers on NPR. Read a summary of the discussion, or listen to it in full, here.