In this chapter, we will present basic structures for strategic form games. These games model situations where individuals choose their strategic actions independently and once. A popular example of these games is the rock-scissors-paper game played by many children all over the world. Section 1.1 will provide the general definition of a strategic form game with pure strategies, followed by various examples; Sect. 1.2 will present some well-known strategic form games that will be used in various chapters of this book; Sects. 1.3 and 1.4 will present two special classes of strategic form games, zero-sum games and symmetric games, respectively; and Sect. 1.5 will present the mixed extension of strategic form games where players are allowed to randomize over their pure strategies.