What is a Pokémon?
A Pokémon is a type of creature found throughout the game's world. There are 150 species of Pokémon known. Some of them will be easy to catch, like Rattata and Pidgey. Others, like Chansey and Mewtwo, will be extremely difficult to catch. Your goal is to catch at least one specimen of each Pokémon. There are currently 250 known Pokémon, but only 150 may be caught in the Blue, Red, and Yellow versions of the game. The other 100 Pokémon can only be caught in the Gold and Silver versions. You cannot catch Mew without a game-enhancement device, such as Game Genie or Game Shark.