Owen, his brother David Dale Owen, and architect Robert Mills, were involved in developing preliminary plans for the Smithsonian Building. These early plans influenced Renwick's choice of the Romanesque Revival architectural style (sometimes referred to as Norman-style architecture) and his three-story design for the building, which was finally selected, although not without controversy. Owen's book "Hints on Public Architecture" (1849) argued the case for the suitability of Renwick's Romanesque Revival (Norman) architectural style for public buildings such as the Smithsonian "Castle," which he discussed in detail. Seven full-page illustrations and details of the building's architectural elements were prominently featured in the book, leading some to criticize Owen for his bias toward Renwick and his preference for Norman-style architecture over other popular styles.