Agreed, but most of the essays I read are precisely made of this kind of contents, so I would have hoped some updated books. Just like most of the best-seller

Agreed, but most of the essays I read are precisely made of this kind of contents, so I would have hoped some updated books. Just like most of the best-seller essays use this type of contents, just read any book from the regretted Stephen Hawking... But if you have any reference textbook that is less "experimental" (in the Debian package meaning), I'm also happy to hear you!!