Apple iWork '09 - Manual (Page 166)

TRUE
The TRUE function returns the Boolean value TRUE. This function is included for
compatibility with tables imported from other spreadsheet applications.
TRUE()
Usage Notes
The TRUE function does not have any arguments. However, you must include the Â
parentheses: =TRUE().
Instead of using the TRUE function, you can specify a Boolean value of TRUE by
Â
simply typing TRUE (or true) into a cell or function argument.
Examples
=TRUE() returns the Boolean value TRUE.
=AND(1, TRUE()) returns the Boolean value TRUE.
=AND(1, TRUE) works exactly the same as the preceding example.
Related Topics
For related functions and additional information, see:
“FALSE” on page 157
“Listing of Logical and Information Functions” on page 155
“Value Types” on page 36
“The Elements of Formulas” on page 15
“Using the Keyboard and Mouse to Create and Edit Formulas” on page 26
“Pasting from Examples in Help” on page 41
166 Chapter 7 Logical and Information Functions