For some forty years Richard P. Feynman focussed his curiosity on the mysterious workings of the physical world, and bent his intellect to searching out the order in its chaos. Now, he has given two years of his ability and his energy to his Lectures on Physics for beginning students. For them he has distilled the essence of his knowledge, and has created in terms they can hope to grasp a picture of the physicists universe. To his lectures he has brought the brilliance and clarity of his thought, the originality and vitality of his approach, and the contagious enthusiasm of his delivery. It was a joy to behold. . The first years lectures formed the basis for the first volume of this set of books. We have tried in this the second volume to make some kind of a record of a part of the second years lectures--which were given to the sophomore class during the 1962-1963 academic year. The rest of the second years lectures will make up Volume III.