A couple days ago, I finished reading Cisco ISP Essentials and took some notes on it. This book was published in 2002, and a lot of the information in the book is now out of date, though several fundamentals are still relevant, which was my motivation for reading it.
Although the book makes some mention of things typically done in larger ISP environments, I think the book catered mostly to small and medium-size ISPs. This book is written from the perspective of the tail-end of the dial-up period, where cable and DSL were just starting to take hold. Everything is a lot more complicated today, and a lot more traffic engineering occurs even at smaller ISPs.
However, at this point in time, this book serves mostly as a “know your roots” kind of text. The fundamentals explained in it are wonderful and serve as a good foundation for moving forward with my network engineering studies.