We may perhaps gain some insight into the real nature of the controversy concerning the extraterrestrial hypothesis (ETH) as an explanation for UFO reports by examining the historical development of the idea of life on other worlds. Our attitudes to this question are determined, to some extent, by the traditional world pictures and world views which we have inherited. 
Jacques Vallee's new book on UFOs ought to come with a Government health warning. Its one redeeming feature is Vallee's sporadic wit; otherwise it will appeal only to sick minds of the type of person that enjoys John le Carre and Dennis Wheatley. I only survived two readings of Messengers of Deception with the aid of much sympathy from my friends, and liberal doses of high volume Stravinsky. .
Those of you who have collected stamps will know that it can be done with considerable excellence. One may specialise in stamps of different periods or countries, in particular subjects or themes. One may take an interest in new issues or postal history, or in forgeries. One may buy catalogues or background books, or expensive items of equipment, or even join clubs and societies for enthusiasts. Stamps being straightforward and inanimate, collecting them is an ideal hobby for children.