This is one of the best methodology textbooks that I've read. I have a quite a few sound reasons for the 5 star rating. In the first place, I must admit that I am a slow reader. But the slowness gives me much time to develop a deep understanding about what I am reading. So far, I've finished reading several methodology texts in the area of social sciences, such as Research design: Qualitative, quantitative, and mixed methods approaches (J. Creswell), Qualitative research design (J. Maxwell), Basics of qualitative research (Strauss & Corbin), and Case study (Yin), the one I am commenting. Comparatively speaking, Creswell's book is a disaster; I recommend Yin and Maxwell. If you choose a methodology text based on the number of citations, you might be tricked.
I don't want to go further with the content of each textbook listed above. I just want to say, when evaluating a textbook, you must ask yourself a question "Can this book really help me with my research?" If the answer is positive, the book is good. Or it is bad. I did not get anything from Creswell after I finished that dictionary-like text. To determine the quality of a text, audience should consider two factors: First, is the writer a researcher? Second, is the writing of the text based on sound research?
If the author is not a real researcher, how could he write a reasonable book to help you understand how to research? The reason for the popularity of Cook and Campbell's (1979) book Quasi-experimentation is that they themselves are brilliant researchers. They know how to research and it is very possible for them to explain and convey the essence of how to do. Seen from this perspective, Yin's book should not be bad because he is a well-known researcher in program evaluation. Note that he received strict training in psychology at MIT. Strauss's book give audience a lot of details. He is the founder of grounded theory. I should say his book is good even for those who does not prefer this method. Maxwell is ok. After all he is hard-working and he also conducts studies in the area of education. I don't recommend Creswell because he is just a writer who is good at piling up information. From his big books, I am not sure if you really can make sense.
At the same time, we must pay attention to the soundness of the literatures on which the textbook writing is based. If the writing is based on empirical studies, it is more possible for the book be successful than those based mainly on explanation, theories, and book chapters without empirical studies. To let audience know how to do research, the text writer should read a lot of empirical studies from which he/she summarizes and conveys the methods of doing research. When you read Yin's book, you will find that the majority literatures that he referred to are empirical ones. Across that book, he recommended many books and articles of empirical research. With the help of Yin and some example books that he recommended, possibly, you will know how to do research. With this said, Strauss's book is good too.