Fishways can be constructed in a technically utilitarian way or in a manner meant to emulate nature. Bypass channels and fish ramps are among the more natural solutions, while the more technical solutions include conventional pool-type passes, slot passes, fish lifts, hydraulic fish locks and eel ladders. All these types are dealt with in this book. Furthermore, particular emphasis is laid on the importance of comprehensive monitoring. These Guidelines deal with mitigation of the upstream migration only as data on improvement of downstream passage was scarce at the time of the preparation of the first edition, published in German in 1996. Therefore, the complex theme of downstream migration is only touched on but not developed in depth.