Henry H. Cook Mansion

In 1880, Cook purchased an entire block in Manhattan for $500,000, but it was not just any block: Cook's block covered the area from Fifth to Madison and 78th to 79th Streets. His own house on the north-east corner of Fifth and East 78th was originally intended to be one four that would mark out each corner of his fiefdom, but that plan never materialized. It was built of white, blue and red granite stone, stacked to create a pattern.

Architectural commentators of the time had mixed reviews of Cook's mansion: the fake chimney that crowns the center of the facade springs improbably from a dormer window, drew particular criticism. But another forgave its architectural misdoings passing it as, "respectable in spite of its monotony and the irrationality of its detail".

By the start of the new century, Cook had become envious of the new Beaux-Arts mansions being put up in Manhattan, in particularly the newly remodelled Whitney Mansion at 871 Fifth Avenue. He asked its designers, McKim, Mead & White, to come up with plans for something similar for him to be built at 973 Fifth Avenue. But, this never came to fruition and instead he retired to Wheatleigh in The Berkshires.     

Ironically, the demolition of Cook's own mansion in favor of the James B. Duke House was the last major residential change to the Cook Block - which remains as possibly the  grandest surviving enclave of what was Gilded Age New York.