Additional chapters of instruction in the writing of photoplays have been included in the belief that they will meet a widely-felt need for accurate information and authoritative advice on this aspect of the silent drama. Though the book is explanatory throughout, a chapter of specific advice to the amateur organization desirous of staging a motion picture has been provided. This is an untouched field in works on pictures, and one that we believe is steadily becoming of interest to a wider circle. R. E. W. NEW YORK, _December, 1915_. A-B-C OF MOTION PICTURES I HISTORY AND PRINCIPLES OF MOTION PICTURES Like practically all other modern mechanical wonders, the motion picture was not the invention of any one man. Rather, the picture as we know it to-day is the cumulative result of the toil and experiments of a score of workers, whose efforts cover over half a century. As far back as 1795 scientists were striving to produce the phenomena of pictures that moved. Succeeding generations all saw experimenters working toward the same object, each contributing his mite of improvement, until, with Thomas A. Edison’s invention of the kinetoscope, in 1893, the day of modern motion pictures dawned. Though all these seekers for knowledge worked constantly with “pictures of objects in motion” as their goal, it is not possible that any saw in the motion picture the possibility of development to its present important place. Dreamers as they necessarily were, there were no imaginations even among picture-men of the last decade that would dare such wide stretches of fancy. No other artistic or industrial development of history will bear comparison with the motion picture’s leap from humble beginnings to exalted favor. Let us go back to the lowly antecedents of the present-day giant. In the year 1830, we find a description of the zoetrope, or “Wheel of Life,” which was introduced in the United States in 1845. Though pretending to be nothing more than a toy, the zoetrope embodied the optical principle that is at the basis of all motion-picture work. It consisted of a revolving cylinder, in appearance much like a common hat-box, with the top removed to permit the light to enter. Vertical slots were made equal spaces apart around the upper half of the cylinder, and ten or more drawings showing a particular object in different positions were placed around the lower half of the interior. The cylinder revolved on a vertical spindle, and the spectator, peering through the slots, received the impression of seeing the object on the interior in motion. Simple drawings were used, a favorite being the figure of a dancer.