There are not two ghost alike. A good ghost buster will approach each one differently.
The existance of ghosts had been accepted by all civilizations in the history of humanity.
It is only with the development of scientific observation that in the last centuries, we started to discuss their
existence and nature. There have been only a few serious attempts to discover that they are real and to study their behaviour. Many persons think of ghosts with a mixture of fear, strange and laughter.
We reject what we don't understand instead of saying to ourselves: "There are more things on the earth and in the sky and in between that we will even dream of. There is more to see than can ever be seen and more to understand than can ever be
understood."
Apparitions are even rejected by the ones who saw them. "I saw it but I can not believe my eyes." is the typical reported reaction. The human mind reject an information which can not be assimilated. Better and more cases must be reported before we can learn this as subject in school.
In spite of a century of intensive research, the questions remain without definite answers. Who are they? In what conditions do they manifest themselves? Ghost busters keep on confronting mysteries...