This is a really well-written book. I worked out all the exercises in it-and learned an enormous amount from doing so. These are not routine and boring exercises, but teach the student how to think and reason rigorously. One is also not overwhelmed by a plethora of routine exercies that really contribute little to one's learning of the subject. It is a great pity that this book is out of print-it didn't stop me from acquiring a used copy and working through it. The theory is covered in a very efficient manner. I found myself returning to the statements of the theorems in this book when I had to use these theorems in my other mathematical pursuits. On hindsight, I have come to realize just how well-written it is. I cannot disagree more with the earlier reviewer who clearly has no appreciation for the process of thinking and working mathematics seriously, or for books that are exemplary pieces of mathematical exposition like this one. Of course, it demands effort-anything worthwhile does. In my case, the effort was amply compensated by the results.