Dr Spencer's account gives, in largely non-mathematical terms, a concise but rigorous explanation of the principles underlying the various forms of light microscopy. It starts with the properties of lenses, elementary diffraction theory and theoretical limits to resolution; it goes on to explain the workings of phase contrast, dark-field, fluorescence, polarizing and interference microscopes. There are chapters on aberrations and photomicrography, and detailed instructions for the alignment and general care of microscopes. Questions and answers are given at the end of each chapter, and suggestions made for class experiments. Although written primarily for undergraduates, the treatment is equally suitable for those preparing for professional examinations in microscopy, and for research workers seeking a better understanding of the microscopes they use.