Clojure is a dialect of Lisp with a focus on functional programming. It was released in 2007 by Rich Hickey, and has since gained a lot of popularity among web developers.

To learn about some of the language's core functions, you can consult the documentation.

You could also consult any of these articles:

• Summary - Why use Clojure?
• Basics - Defining some variables and functions.
• Conditionals - Using logic to add complex control flow to your programs.
• Let Bindings - Using local variables.
• Loop and Recur - Using recursion to create loops in Clojure.