Welcome to JavaRanch and congratulations on writing a Book on such a Hot topic. I have never used it in any application but we have had some training within the company. One of my teacher said until you know the reason behind the existence of something you will never understand the real value of it. I have read some articles and documentation of Scala. But I am unable to find out the reason why we have Scala . So I want to check with you. Did you cover the reasoning behind the existence of Scala? Like if Scala provides a feature A do we really need it and why? What was the existing problem that we are trying to solve with Scala. Thanks again for your book. I am sure it will rock!