Standard Library - clojure.core
Examples of using the functions from the clojure.core namespace and other important functions, macros and special forms that are part of the org.clojure/clojure library.
Functions, Macros and Special forms
The majority of times macros and special forms act just like any other defined function (i.e. fn, defn)
A macro is a piece of code that evaluates into a function when read by the macro reader, or by the developer using macroexpand function. An expanded macro may also contain macros, so expansion could take place several levels (macroexpand-all).
macros are not composable like functions, so functions like apply reduce map cannot use a macro (use a function instead).
Special forms are built into the Clojure runtime, so will not be found in clojure.core