"Life of a Mansion" tells the story of the building that Cooper Hewitt, Smithsonian Design Museum calls home. It details how Andrew Carnegie's grand but functional Fifth Avenue mansion--which was pioneering in its design, with an electric elevator and modern steel-frame construction--was constructed. The book features the rooms in which Carnegie conducted his business and philanthropic endeavors, and where the family and staff lived and entertained throughout the mid-twentieth century. It also surveys plans for the 1976 renovation by Hardy Holzman Pfeiffer (when Cooper Hewitt first opened as a public museum) and the building's latest extraordinary renovation by Gluckman Mayner Architects, executive architect Beyer Blinder Belle and world-renowned Diller, Scofidio + Renfro, which has positioned Cooper Hewitt as a truly twenty-first-century design museum. Upon completion of three years of intense work, the new building has been LEED certified, and has gained an additional 6,000 square feet of gallery space. With an engaging narrative illustrated by 200 photographs, maps, floor plans and letters, "Life of a Mansion" chronicles the 110-year history of the National Landmark building, as well as the evolution of the museum from its establishment by the Hewitt Sisters in 1897 to its status post-renovation in 2014 as the site of the nation's design authority.