I received a free copy of this book in order to write my standpoint on it.
I think if you are new to cognos, or if you worked with Microsoft SQL Server Reporting Services, and want to migrate to cognos this book is very nice to follow.
Indeed, it makes the learning of cognos easier by providing lots of examples which are describes with lots of pictures.
Honestly, I think if you are professional in one reporting tools, you don't need any book, and you can just surf the tool and follow the help to overcome its difficulties.
By the way, if you are not a guru on any reporting tools, or if you do not have enough time to spend on the cognos to migrate from SSRS, I strongly recommend this book.
This book is not going to introduce any concept or any sophesticated techniques on reporting. However, it provides easy to follow step by step instructions to get familiar with the IBM Cognos 8 Report Studio.