The science and art of crystal growing continue to flourish; even with increasing understanding of the science, feel and skill continue to play their vital part, as was so clearly evidenced at the recent Boston International Conference on Crystal Growth. The aim of this volume, the same as that of the first, is to try to improve understanding by providing detailed discussions of crystal growth techniques and problems that arise with them. The published paper in the specialized literature is too limited a vehicle, by convention and by editorial pressure on length, to discuss matters in detail, yet it is in the small details born of experience that vital information can often lie concealed. A major aim of this series, therefore, has been to encourage contributors to describe rather fully what has been achieved in their special fields. The next volume of this series is now well underway and plans for Volume 4 are advanced. If you, the reader, feel that some important aspect of crystal growth is being unjustifiably neglected, perhaps you should consider offering a contribution! And even if you do not wish to do that, please do offer criticism-preferably constructive. I hope that the present volume will prove as useful and interesting to crystal growers as apparently did the first volume of the series; certainly the warm commendations that that volume has elicited were a great encouragement for the present work. Finally it is a pleasure to thank Standard Telecommunication Laboratories for its continuing support.