Sanford Gifford (1823–1880), a leading Hudson River School landscape painter and a founder of The Metropolitan Museum of Art, was so esteemed by the New York art world that, at his untimely death, the Museum mounted a show of his work―the first monographic exhibition accorded any artist―and published a Memorial Catalogue that, for nearly a century, remained the principal source on his oeuvre. Gifford's art, which was inspired by the work of Thomas Cole, the founder of the Hudson River School, and by that of J. M. W. Turner, and was enriched by his travels in Europe (from 1855 to 1857, and from 1868 to 1869), came to be called "air painting," for he made the ambient light of each scene―color saturated and atmospherically potent―the key to its expression. His approach to painting and his unique style gave rise to a highly distinctive body of work, of enchanting and mesmerizing effect. While Gifford himself compiled a "List of Chief Pictures" late in his career, a significant part of his extant oeuvre consists of small-scale studies, preparatory works in oil, and original drawings, most of which are in annotated sketchbooks and document the progression from on-site record to idealized vision achieved in his major pictures. The four essays that open the catalogue―which accompanies the first exhibition of Gifford's work since 1970―examine the artist's place in the Hudson River School (Franklin Kelly), his numerous Catskill Mountain subjects (Kevin J. Avery), his experiences and perceptions as a traveler both at home and abroad (Heidi Applegate), and the variety of his patrons (Eleanor Jones Harvey). Following are entries by Avery and Kelly that discuss in detail the seventy paintings by the artist in the exhibition; each is shown in color and many are supplemented by comparative illustrations of related works by Gifford, his Hudson River School mentors and colleagues, and those painters, in addition to Cole and Turner, who exerted some influence on his art―among