Contacting the dead

For many years Spiritualism has intrigued me. Are those mediums who are supposedly giving out messages from the dead merely hallucinating or are they really able to contact the deceased?
Having done much research in this area, including attending spiritualist meetings, I decided to write about the subject in my next novel 'Deadly Partnership' which is to be published soon. I would be interested to receive the comments of others on Spiritualism. Let me know what you think.