Four years ago several NATO nations agreed to commence studies to develop tactics for ASW Area Search. The combined approach required agreement on the scope of the problem, tactical doctrine, modelling parameters and definition of terms. The NATO Area Search and Screening Working Group (AS2WG) is progressing development of tactics with a collaborative programme of OA modelling using existing national models to provide search algorithms. Most of this modelling is being conducted in the Netherlands, France and in the UK. This paper describes the approach taken to develop and document a common doctrine. It also describes in general terms the output of the AS2WG, both in the development of NATO ASW Area Search tactics and the definition of a requirement for a PC-based Tactical Planning Aid to be developed by NATO to assist in solving the Area Search problem.