I don't buy as many physical books as I used to; mostly fiction, and mostly used.

I buy a fair number of ebooks, mostly technical, and mostly from O'Reilly. I love that they're DRM-free; in my case I take the PDF version, but they have other formats.

Pakt has a very low-intrusiveness form of "DRM." They print your name on every page of the pdf that you buy, but it's otherwise unrestricted.

I don't think Pakt or O'Reilly is going to come after you for sharing an ebook with a family member, and I've given a few copies of O'Reilly books to colleagues, to evangelize both O'Reilly and the tech in question.