What is cool about Smalltalk?
Smalltalk is an object-oriented programming language with a uniform programming model. Unlike many other languages, learning the Smalltalk programming language is easy because there are just a few concepts to grasp. Everything is an object in Smalltalk (including number, string, character, code blocks, and classes themselves), and everything is done through a single paradigm, that of sending messages from one object to another.
Many cool and revolutionary ideas were conceived from the Smalltalk community, including the very idea of window-based, graphical user interfaces. Smalltalk systems are open, as source code for every class is available and modifiable, including all the kernel classes; being free software, GNU Smalltalk extends this openness to the virtual machine, and complements it with the freedom to redistribute and publish your improvements.