Even the preface to the 2006 edition suggest that they think of it as, largely, a graduate level text:

> It takes at least two quarters or even two semesters to cover all or most of the material in this book. It is common to cover the first half in an undergraduate course and the second half of the book -- stressing code optimization -- in a second course at the graduate or mezzanine level.

Dragon book is a weird one. While a classic, it only decently covers basics of the theory of computation, while only doing a brief run through the rest of compilers.

None of modern grad-level compiler topics are decently covered. The dragon is also not a very practical book.

Tiger book is a much better introductory read, balancing between practical and theoretical aspects.

Most truly advanced compiler topics are not really covered by any single book.