Alex has had numerous posts on Modern Principles, but here is my two cents. A textbook, as the name indicates, is a book. It has to be conceived of as a book, and thought of as a book, and written as a book, and ideally it should be read as a book. There are many other textbooks out there, and I do not wish to name names, but consider the following question. Which are the authors who really love books? Who spend their lives reading books? And indeed writing books. And who spend their lives studying what makes books good or bad? Who view books as truly essential to their overall output?
An ancillary question to ask is who are the authors who are truly dedicated to video, and to on-line communication more generally, as an independent outlet for their efforts and creativity?
Here is information on our new fifth edition, better than ever. Because we love books.