An instruction manual, in the context of computer and video games, is a booklet that instructs the player on how to play the game, gives descriptions of the controls and their effects, and shows a general outline of the concepts and goals of the game. It is also common for manuals to contain a brief summary of the storyline of the game, especially in games with complex storylines, such as role playing games. Manuals can be very large, such as the hundreds of pages for Civilization II, or very small, such as the single sheet of double sided A5 paper included with Half-Life 2.