The Wave Principle is Ralph Nelson Elliott's discovery that social, or crowd, behavior trends and reverses in recognizable patterns. Using stock market data as his main research tool, Elliott isolated thirteen patterns of movement, or "waves," that recur in market price data. He named, defined and illustrated those patterns. He then described how these structures link together to form larger versions of those same patterns, how those in turn link to form identical patterns of the next larger size, and so on. In a nutshell, then, the Wave Principle is a catalog of price patterns and an explanation of where these forms are likely to occur in the overall path of market development.