I am a social scientist, not an epidemiologist, and I found this book to exceptionally good. It is the most current, complete, and clear presentation of methods for causal inference for observational (i.e. non-experimental) studies that I have seen. The things that really set this book apart for me include:
1. It synthesizes contributions by Pearl and Rubin on the foundations of causal inference, and contributes its own perspective via the sufficient cause model. This is truly cutting edge, not to mention impeccably coherent.
2. The first third of the book is on study design, including measurement, sampling, and defining effects. This is just fantastic. Many methods textbooks jump right into approaches to analyzing data with little time taken to discuss how to make the data in the first place. This book provides a major corrective to that tendency.
3. In data analysis, a lot of attention is given to sparse data problems, which again is just great. So many textbooks overlook this problem, which is a huge omission.
4. The data analysis section includes discussion of up-and-coming data mining and non-parametric methods (e.g. BART, boosted regression, etc.) to characterize response surfaces in the service of causal inference. That's amazingly cutting edge for a textbook.
5. The meta-analysis section emphasizes simplicity and provides a very nice list of common errors that should be avoided.
6. The references are to state of the art literature not only in epidemiology, but also in econometrics, education research, and statistics. It's great to see such cross-fertilization across disciplines, and it shows how these various disciplines are converging, it seems, on common analytical tools for causal inference in observational studies.
There are lots of nice examples throughout the book too. For other social scientists out there, I highly recommend this as a primer on state of the art methods for carrying out observational studies.