The idea of writing an account of the achievements of JET in a coherent way for a wider readership arose a few years ago when it became clear that JET as a Joint Undertaking would end in 1999. I was convinced that such a book, if well written, would serve an important purpose not only for JET but for the European Fusion Community at large. I was therefore extremely pleased when John Wesson agreed to attempt this difficult task immediately following his retirement, while the JET history was still fresh in his mind. The JET Project truly deserves to be remembered and honoured in this way. It is fair to say that JET has been one of the most successful joint ventures in Europe, not only from a scientific point of view but also as one of the most efficient organisations in Big Science. Here I would like to record our debt to the founding fathers of JET: Donato Palumbo, the then Director of Fusion in the European Commission, who used his great perseverance and immense diplomatic skill to steer this large project through all obstacles to its approval in 1978. Hans-Otto Wüster, the first Director of JET, who successfully set up the complex administrative, scientific and engineering structure of the project and fostered such a splendid team spirit among its staff. And finally his successor as Director, Paul-Henri Rebut, who must be remembered both for his vision and drive in the design and construction of this great machine and for his contributions to its scientific success. They have all shown themselves to be men of great foresight, courage and dedication.