That is strange! I got the Dutch version of this writing by a Dutchman. The first pressing is of 2000 and the fourth of 2003. Amazon gives an out of print 1902 pressing?!? I suppose this is a mistake. Anyway, Waaijman is professor of spirituality in Nijmegen, Netherlands. He wrote this purely scientific book about the subject. This massive book (almost 1000 pages) is divided in three parts. In the first part Waaijman speaks about different forms of spirituality, in the second he investigates the subject and in the third he describes the methods for investigation that he recommands. Large parts of this book will not be interesting for the layman, but because of the descriptions of many movements and groups, it is still a very nice refference-work. A minor point is that Waaijman limits himself to major currents. The world religions are spoken about and a little bit of aligned subjects. Islam with sufism for example, or Judaism with Kabbalah, Christianity with gnosis, mysticism, theology or dialectics, but also Buddhism, Hinduism, Taoism and the like. (Almost) no esotericism, but I suppose this subject is less ‘scientifically investigatable’ and another volume of 1000 pages would be needed. All in all a nice reference work, partly not for the common man, so I advice that you try to page through a copy to see if this is something for you before you actually buy it.