I am struggling to understand the relationship between electromagnetism, electromagnetic fields and electromagnetic radiation. I understand that a moving electric charge creates a magnetic field and a moving magnetic field creates an electric charge and that this is the foundation of electromagnetism. Does this make an electromagnetic 'field' or are there only electric and magnetic fields separately? Also, how does electromagnetic radiation fit in with this, fields seem to exist around the source while radiation is propagated in a straight line from it. How do they relate to each other?