FOREWORD R S Pease, Director of Culham Laboratory (1967 - 1981) I was young, I and other children of the nineteen thirties were introduced to scientific endeavour and adventure by books such as 'Men who Found Out', where the discoveries in science are justly attributed to the outstanding genius of specific scientists. Of course the great men and women - Pasteur, Davy, Faraday, Madam Curie - had their assistants, spouses or close relatives to assist in the research, the achievements were essentially individual. Even as we absorbed these thrilling accounts of the conquests of diseases and the mastery of electro-magnetic waves by combat, so to speak, the pattern of individual hagiography was being undermined. Physicists in Cambridge and California were developing the application of engineering to physics research and its concomitant techniques, of which the team method of research is pre-eminent. Men such as Cockcroft, Oliphant, Allibone and Kapitsa at Cambridge, Lawrence and McMillan at Berkeley, employed engineering industry to develop and build their apparatus, increased the laboratory budgets by several orders of magnitude (indeed openly boasting of this latter achievement) and introduced team research to nuclear physics. The age of innocence was passing. The history of physics thenceforth becomes much more akin to military history, where the great men are the commanders and the quarter-master generals, where the views of politicians and of the tax payers have to be taken into account, and where the role of the military intelligence is played by the theoretician. Moreover the operations, or at least their results, are the subject of widespread and legitimate press comment, adding a new dimension to the rewards and hazards of research. Just as military campaigns of dubious value or disastrous consequences have a lesson for us all and are the stuff of history, so too are the not always wholly successful research campaigns of modern physics - amongst which are some of the developments of nuclear energy. The successes and their impact on society are indeed recorded, but much of the interest lies in the inner history of human interaction in the highly technical environment. Whole armies of research workers can be marched in the wrong direction by mistaken intelligence or pigheaded commanders. Many readers will be amazed that laboratory directors, like generals, are not more perceptive, or at least more cautious, and that scientists allow the undoubted pressure of events, as well as human emotion, to affect decisions. In both cases, the undertaking of history has another, more serious purpose, namely that of the post mortem. What actually happened? Why did the Duke of York march 10,000 men up the hill? Who is to blame? Who should take the credit? As Winston Churchill said, the purpose of recrimination is to enforce effective action in the future. Here, at last we come to the nub and substance of this history of nuclear fusion by Hendry and Lawson: for fusion research is one of the most colourful of these research campaigns. It has at least one major episode, the affair of the Zeta experiment at Harwell, where the excitement of the research overrode the judgement of the By R S Pease, Director of Cuiham Laboratory (1967 - 1981) When I was young, I and other children of the nineteen thirties were introduced endeavour and adventure by books such as 'Men who Found Out', where attributed to the outstanding of specific Of course the great men and women - Pasteur, Faraday, Curie - had their assistants, spouses or close relatives to assist the research, but achievements were essentially as absorbed these thrilling conquests diseases and the mastery of electro-magnetic waves by single combat, speak, the pattern of individual hagiography was in Cambridge California developing the application to and concomitant techniques, of which the team of research pre-eminent. such as Cockcroft, Allibone and at Cambridge, Lawrence at employed build their the laboratory budgets by orders of magnitude (indeed openly boasting of this achievement) and team research to The of innocence was history physics thenceforth becomes more akin to military history, the men the commanders and the quarter-master generals, where of and of the tax payers have to be taken into account, and where intelligence is played by the theoretician. Moreover or their results, are the subject of widespread and legitimate press adding a new dimension to the rewards and hazards of research. as military campaigns of dubious or disastrous consequences and of history, so too are the not always wholly campaigns of modern - amongst of the of nuclear energy. The successes and their impact on society recorded, but much of the interest lies in the inner history of human in the highly technical environment. Whole armies research workers in the wrong direction by mistaken intelligence or pigheaded Many readers will be amazed that laboratory directors, like perceptive, or at least more cautious, and that scientists allow pressure of events, as well emotion, to affect the undertaking of history has another, more purpose, namely of the post mortem. What actually did of York march men up the hill? Who is blame? Who should take As Churchill said, of recrimination enforce future. Here, we come to the nub and substance of this history of nuclear fusion by Hendry and Lawson: for fusion research is one of the most colourful of It has at least major episode, the affair of the Zeta experiment Harwell, where the excitement of the research overrode judgement 1 commanders, and left a lasting impression of the nature of nuclear physics research on politicians and public alike. The research has as a goal a form of energy which, if successfully developed, will rival and supplant conventional nuclear fission. Consequently the political pressure on its scientific leadership is very considerable. Lawson and Hendry are especially well qualified to write this history of how the leaders and the workers responded to these pressures. Lawson worked at Harwell during the crucial years; he is renowned for his pioneering analysis - the Lawson criteria - encapsulating the technical objectives of the research; and yet he stood sufficiently far above the melee to preserve independence of judgement. Hendry's experience of the history of nuclear energy as a whole provides the overall background and the professional historian's discipline. Both have been thorough in their exploration of the original documentation and severe in cross-examination of the surviving actors. How fusion research in the United Kingdom started, how it developed, got into great difficulties and how it recovered, is the essence of their story. Their lesson has a particular as well as a general significance, because fusion research is not yet successfully consummated. The present round of experiments on the Joint European Torus, JET apparatus at Culham has yet to be completed; their results, when they are available, will be used to decide, together with all other factors, whether or not to proceed with the 'International Tokomak Experimental Reactor' now being designed by a world team of engineers and scientists. This decision will be the next major milestone in magnetic fusion research. I am sure that this history will instruct, inform and entertain the public at large about the nature of major research programmes. But it will also help those who have to lead the way forward in research on controlled nuclear fusion in the years ahead. 10 January 1993