Assuming a basic knowledge of probability and modern algebra, this book gives an introduction to information and coding theory at the graduate or advanced undergraduate level. It describes the fundamental issues involved in these subjects.
This book is "information theory-light" (approximately 120 pages) and "coding theory-heavy" (approximately 300 pages).
The book covers many families of codes and this is definitely its strength. In light of the series title, "Graduate Texts in Mathematics", and in view of it being published by Springer-Verlag, this text is not an "easy read". It likely works best as a strong reference for encoding/decoding theory in a general context of information theory.
If you are a beginner in coding theory in mathematics and computers, I would suggest this book to get acquainted with the nuts and bolts. Obviously, this text is crucial for graduate students, professors and post-docs in the area. If you are a beginner in information theory, I would suggest another book!