This Advanced Study Institute was arranged to discuss in depth the physical and technical basis of the latest developments in methods of measurement and image analysis suitable for determining the prop­ erties of cells and tissues and for evaluating medical structures. All topics under consideration have benefitted dramatically from an injection of new ideas during the past 10 years, and some have developed even more recently. The Institute brought together lecturers and participants from 14 different countries, and the subject matter recorded in this volume may be considered under two general headings. The first part of the meeting concentrated on techniques that are most appropriate at the cellular level. One major area of develop­ ment has been centered on attempts to classify cells by computerized ex­ traction of visual features, and here, it was notable how different techniques frequently complement each other. This part of the meeting also examined mechanisms of damage at the cellular level caused by different forms of radiation, and the contrasting effects of ionizing radiation, ultraviolet light and ultrasound were highlighted.