 While the ONA has stated that it is not an occult organization in the conventional sense but an esoteric philosophy, several academics have written about ONA membership. In a 1995 overview of British Satanist groups, Harvey suggested that the ONA consisted of less than ten members, "and perhaps fewer than five." In 1998, Jeffrey Kaplan and Leonard Weinberg stated that the ONA's membership was "infinitesmally small", with the group acting primarily as a "mail-order ministry". Regarding the question of membership, Anton Long, in a letter to Aquino dated October 1990, wrote that "once the techniques and the essence [of the ONA] are more widely available then membership as such is irrelevant, since everything is available and accessible ... with the individual taking responsibility for their own development, their own experiences."
