What language are you talking about? Ruby? Groovy? JavaFX? This forum is for all object oriented scripting languages. Also your question is not really clear. What do you mean by why a language is created?
I assume that you are asking about ruby, since this week's book is on it. Well, ruby is a dynamic (and dynamic typed) language created by Yukihiro Matsumoto, and released to public in 1995. Like any other programming language, its creator wanted something that wasn't available in the languages available at the time of creation. One of the things is following th principle of least surprise (POLS), high portability, loading of DLLs/shared libraries dynamically on most platforms, small learning curve, large standard library, and of course the reduced number of lines of code the programmer needs to write.
Any language has its advantages, and has a place where it excels, and knowing this, integration of languages is a must, so that you can create systems that use multiple languages. Sun did a very wise move by supporting scripting languages, like ruby and groovy, in the java platform.
As for the book, the editorial review on amazon says that the book is for "Ruby and Rails developers seeking to create compelling business intelligence and reporting solutions using a wide variety of applications and services." [ February 06, 2008: Message edited by: Alaa Nassef ]