A built-in boolean type. The [bool] is a built-in [Variant] type that may only store one of two values: [code]true[/code] or [code]false[/code]. You can imagine it as a switch that can be either turned on or off, or as a binary digit that can either be 1 or 0. Booleans can be directly used in [code]if[/code], and other conditional statements: [codeblocks] [gdscript] var can_shoot = true if can_shoot: launch_bullet() [/gdscript] [csharp] bool canShoot = true; if (canShoot) { LaunchBullet(); } [/csharp] [/codeblocks] All comparison operators return booleans ([code]==[/code], [code]>[/code], [code]<=[/code], etc.). As such, it is not necessary to compare booleans themselves. You do not need to add [code]== true[/code] or [code]== false[/code]. Booleans can be combined with the logical operators [code]and[/code], [code]or[/code], [code]not[/code] to create complex conditions: [codeblocks] [gdscript] if bullets > 0 and not is_reloading(): launch_bullet() if bullets == 0 or is_reloading(): play_clack_sound() [/gdscript] [csharp] if (bullets > 0 && !IsReloading()) { LaunchBullet(); } if (bullets == 0 || IsReloading()) { PlayClackSound(); } [/csharp] [/codeblocks] [b]Note:[/b] In modern programming languages, logical operators are evaluated in order. All remaining conditions are skipped if their result would have no effect on the final value. This concept is known as [url=https://en.wikipedia.org/wiki/Short-circuit_evaluation]short-circuit evaluation[/url] and can be useful to avoid evaluating expensive conditions in some performance-critical cases. [b]Note:[/b] By convention, built-in methods and properties that return booleans are usually defined as yes-no questions, single adjectives, or similar ([method String.is_empty], [method Node.can_process], [member Camera2D.enabled], etc.). Constructs a [bool] set to [code]false[/code]. Constructs a [bool] as a copy of the given [bool]. Cast a [float] value to a boolean value. Returns [code]false[/code] if [param from] is equal to [code]0.0[/code] (including [code]-0.0[/code]), and [code]true[/code] for all other values (including [constant @GDScript.INF] and [constant @GDScript.NAN]). Cast an [int] value to a boolean value. Returns [code]false[/code] if [param from] is equal to [code]0[/code], and [code]true[/code] for all other values. Returns [code]true[/code] if the two booleans are not equal. That is, one is [code]true[/code] and the other is [code]false[/code]. This operation can be seen as a logical XOR. Returns [code]true[/code] if the left operand is [code]false[/code] and the right operand is [code]true[/code]. Returns [code]true[/code] if the two booleans are equal. That is, both are [code]true[/code] or both are [code]false[/code]. This operation can be seen as a logical EQ or XNOR. Returns [code]true[/code] if the left operand is [code]true[/code] and the right operand is [code]false[/code].