FRONTISPIECE, an architectural term for the entrance front of any building, also, more commonly, for a rich decorative feature of considerable size, sometimes including the entrance door, applied to the principal front of a building. Thus the tall niches containing the doors of many Mohammedan buildings (see MOHAMMEDAN ARCHITECTURE) are frontispieces. In common non-architectural usage the word designates the decorative com position or picture placed at the beginning of a book, usually facing the title page, and forming the first, and often the most important of the book's illustrations.