The book treats all aspects of solar magnetism, from its origin in the solar dynamo to its evolution annd dynamics that create the variability of solar phenomena, from its well-known 11-year activity cycle to the ever-changing pattern of sunspots and active regions on the Sun. Several contributions deal with the solar dynamo, the driver of many solar phenomena. Other contributions treat the transport and emergence of the magnetic flux through the outer layers of the Sun. The coupling of magnetic fields from the surface to the solar corona and beyond is also described, together with current studies on the predictability of solar activity.