true false

The true and false keywords have two uses:

1. As literal Boolean values

var myTrueBool = true;
var myFalseBool = false;

1. As operators that can be overloaded

public static bool operator true(MyClass x)
{
    return x.value >= 0;
}

public static bool operator false(MyClass x)
{
    return x.value < 0;
}

Overloading the false operator was useful prior to C# 2.0, before the introduction of Nullable types.

A type that overloads the true operator, must also overload the false operator.