This monograph was written for the conference on the New Instructional Materials in Physics, held at the University of Washington in summer, 1965. The approach is phenomenological and microscopic, and is intended for college students who are not preparing to become professional physicists. The monograph has three sections. Section I includes a short review of the discovery of magnetic phenomena, and a discussion of the concepts of magnetic poles, magnetic field intensity, magnetic moment and magnetic flux. Section II deals with the magnetic interactions of steady currents. Basic calculus is used to reformulate the major concepts of magnetostatics in section III. Some problems for discussion are included in sections I and II. (LC)