Mr. Exman, who wrote about The Brothers Harper (1965), now presents a biography of ""the intangible entity that can best be described as the ""House of Harper"" currently celebrating its 150th birthday. Harper's distinguished history since 1817, when it was founded on ""character, not capital,"" has included many of the foremost authors both British and American. Its enterprises have extended influentially through the Weekly (starring Curtis and Nast, whose Tammany Tiger, Democratic donkey and Republican elephant are a national legacy), the Monthly, the Bazaar as well as book publishing for juvenile and adult readers. While Mr. Exman has ""endeavored to assay debits as well as credits even though admitting ""a natural bias"" in favor of his subject, it is the credits and the accomplishments that emerge here, with a minimum of politicking (aside from mention of Mayor James Harper's position) or finances (aside from the Harvey regime) in view. The life blood of the house--its authors, administrators, editors, illustrators, are here, without much of the life (the Manchester affair receives a decorous paragraph). This is writing for the records and can be read and referred to as such.