[1][2] In his research and publications, Gruenschloss is concerned with interfaith matters, especially the empirical analysis of inter-religious perceptions and forms of trans-religious hybridization.
[3] In Der eigene und der fremde Glaube: Studien zur interreligiösen Fremdwahrnehmung in Islam, Hinduismus, Buddhismus und Christentum (1999), he wrote about how members of one religion perceive those belonging to other faiths; he argues that as each religion postulates that it has privileged access to the knowledge of how things should be, it fails to see others as they really are, only ever perceiving them from a self-referential perspective as different: assuming a religious identity simultaneously creates the "other".
[4] Gruenschloss has also written about new religious movements, notably UFO religions such as Raëlism and Fiat Lux, as well as Scientology and authors such as Erich von Däniken or Graham Hancock.
The thought that there should be angels or aliens overseeing human development is profoundly consoling; and members' sense that they are becoming "light workers" by joining such a movement allows them to feel enhanced self-worth, as they believe they are among the chosen few destined to prepare the New Age.
[5] Lastly, Gruenschloss says, as the established religions lose their mass appeal, it is only natural that some will be attracted to "freelance" spiritual workers; he sees the most effective response to this development not in an assertion of church tradition, but in retaining the ability to engage in dialogue.