'Claiming Knowledge propose une analyse fort pertinente des modalités de la construction du savoir religieux dans la modernité. Ce livre est une contribution importante à l’histore de l’ésotérisme occidental en particulier et des productions religieuses de la modernité en général.'David A. Palmer, Justificatif, 2004.'Hammer has done a great service with his careful analysis of an understudied phenomenon in contemporary religion: the New Age. This book is a treasure of research into the roots and development of modern esotericism…offers new insight…strong book, which certainly deserves a place in the stacks of academic libraries.'T.A. Forsthoefel, Choice, 2001.