Because some Lisp data objects are used to represent programs, one cannot always notate a constant data object in a program simply by writing the notation for the object unadorned; it would be ambiguous whether a constant object or a program fragment was intended. The <#30#>quote<#30#> special form resolves this ambiguity.
There are two kinds of variables in Common Lisp, in effect: ordinary variables and function names. There are some similarities between the two kinds, and in a few cases there are similar functions for dealing with them, for example <#31#>boundp<#31#> and <#32#>fboundp<#32#>. However, for the most part the two kinds of variables are used for very different purposes: one to name defined functions, macros, and special forms, and the other to name data objects.