For most people, life after death is the great unknown, one that can be theorized about but can never be understood fully until the last great journey. For a medium, it is as accessible as a transatlantic phone call.
Okay, being a medium is not as easy as making a phone call. Mediums use a variety of techniques to hear or feel the presence of the deceased, such as heightening their senses of empathy or inviting possession. They function as a vessel to allow living relatives to communicate with deceased loved ones.
Most colleges do not exactly offer degree programs in developing one's psychic abilities, although there are special courses online or in-person on clairvoyance and communication with the dead. Many mediums develop their abilities through self-study or working with an established professional. Mediums also need to be experts in the less glamorous side of running a business talking to the dead, such as advertising and customer service.