GIPF is a strategic game for two players based on a classic concept: in turns, players introduce one piece into play until achieving four-in-a-row. Players then remove their row and capture any of their opponent's pieces which extend that row. This principle of capturing pieces creates each time again completely changed situations on the board. The purpose is to form successive rows of at least 4 pieces, until the opponent has no piece left to bring into play.
(This description was copied from the official GIPF web-site. For more info about the GIPF-game, check http://www.gipf.com)
This manual does not contain the rules for GIPF. If you don't know the game yet, go and buy it or check the GIPF homepage.