Albert Einstein and Leopold Infeld explain the dramatic changes which the science of physics underwent between the time of Isaac Newton and the 20th century.

With some 80 illustrations, the authors embark on a lively and plain-spoken account of scientific principles, pledging in the preface to embark on a simple conversation with the reader. The struggle of the human mind in understanding and explaining the various physical phenomena of the world and universe resulted in a succession of theories as centuries passed. Successive improvements of equipment for experimentation and advent of the scientific method led to better measurements of physical phenomena.

Since this book seeks to explain physics for the general population, it contains no advanced mathematics. Instead, the authors rely on numerous drawings and several photographs of relevant phenomena. Explanations are accomplished with examples of real world objects; cars on the roads, or rollercoasters in the theme park, being relied upon to explain aspects of velocity and motion. More complex aspects of the science, such as quantum mechanics and the attributes of heat, are described in simpler terms and with use of analogy.