Using relevant diagrams and pictures to illustrate concepts discussed, this is a straightforward introduction to quantum physics, focusing on the nature of light and the atom. Written for the student who may have difficulty understanding physics concepts in basic textbooks, the book describes current theories and concepts, explaining how physicist Niels Bohr took the ideas of Max Planck and Albert Einstein and applied them to the model of the atom, changing our understanding of the basic building block of the physical world.