IPI began as a cooperative partnership between Nellie’s English Books and The English Resource in September 2001. Based in Tokyo, IPI operates as a wholesaler of ELT books and materials for various publishers from Japan and overseas.

IPI does not sell directly to end-users, but instead acts as an intermediary between booksellers and various independent publishers. The wide selection of materials that is offered rivals that of all the major ELT publishers in Japan.