what is Ruby?

Ruby is a reflective, object-oriented programming language. It combines syntax inspired by Perl with Smalltalk-like object-oriented features, and also shares some features with Python, Lisp, Dylan and CLU.
Ruby is a single-pass interpreted language. Its main implementation is free software distributed under an open-source license.

According to the Ruby FAQ, "If you like Perl, you will like Ruby and be right at home with its syntax. If you like Smalltalk, you will like Ruby and be right at home with its semantics. If you like Python, you may or may not be put off by the huge difference in design philosophy between Python and Ruby/Perl."

advantages of Ruby

Ruby has been described as a multi-paradigm programming language: it allows you to program procedurally (defining functions/variables outside classes makes them part of the root, 'self' Object), with object orientation (everything is an object) or functionally (it has anonymous functions, closures, and continuations; statements all have values, and functions return the last evaluation). It has support for introspection, reflection and meta-programming, as well as support for threads.
Ruby features dynamic typing, and supports parametric polymorphism.

(source: Wikipedia )

relevant books about Ruby

• Programming Ruby: The Pragmatic Programmers' Guide, Second Edition

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