Lawrence Foster, a non-Mormon historian of Mormon history, has offered a mixed assessment of the Tanners and their work. On the negative side, Foster has written that, until the Tanners "are prepared to abide by accepted standards of scholarly behavior and common courtesy, they can expect little sympathy from serious historians." He criticized them for "a holier-than-thou stance, refusing to be fair in applying the same debate standard of absolute rectitude that they demand of Mormonism to their own actions, writings, and beliefs… The Tanners seem to be playing a skillful shell game in which the premises for judgment are conveniently shifted so that the conclusion is always the same—negative."