Religious beliefs and practices which are held in parallel with (or in association with) those of the official religion to which the person concerned belongs: it is thus closely associated with non-official religion. They include such items as superstition and the paranormal. The term invisible religion was introduced by the german sociologist thomas luckmann and became widespread following the publication in 1963 of das problem der religion in der modernen gesellschaft, published in english as the invisible religion: the transformation of symbols in industrial society. This book shall reflect on the term "invisible religion" and will go in depth to understand what it truly means and what thomas luckmann wanted to express through this term.