This book is very well written by Isabella Peters. The translation is also very good. It is easy to read and compares many different views on this rather young topic. Many research papers are referenced and discussed. I find it a very comprehensive book in this area, always giving mention to further literature for further reading. It gives enough background for anyone to understand the required terms and models (like Vector Space Model) but also gives a good overview of current tools and services. Then various open issues are discussed giving advantages and disadvantages of various approaches and solutions. I strongly recommend this book to researchers in this field.