I really enjoyed this interview from 2011 with Laurence King,
"The market for digital illustrated books was always going to move more slowly than for text-only books, but it has developed less rapidly than I anticipated,
and in design and art is more-or-less negligible except for the sale of student books to “for profit” colleges, which sell them along to students as part of the price of the course.
Despite this, I feel sure that in the end the market for illustrated books that are content-driven (such as student, reference and how-to books) will become mainly digital. In the end, publishers’ costs for digital illustrated books will be much lower than for printed books, so publishers will try harder to tempt the market into digital products — not just with lower prices, but more importantly by exploiting digital possibilities. At the moment, digital illustrated books are only a major additional cost with little revenue attached, but I do not think that anyone in the art and design area has created one properly yet."
This looks good, Book Design by Andrew Haslam. I will be teaching a typography course in the spring at ECUAD, and I will add this to the recommended reading