Now, he's giving it all to the Harwood Museum of Art in Taos.
Museum director Susan Longhenry says Foster's gift puts the Harwood on the map. It's considered one of the foremost collections of contemporary art in the Southwest.
The museum is planning an exhibition featuring a portion of the collection next summer. Before that can happen, each piece must be cataloged and transferred to the museum.
Foster says it could be the end of the year before the "big undertaking" is complete.
The collection includes the work of more than 80 artists, including Ken Price, Larry Bell and Ron Davis. Many of the artists were part of Taos' famed art colony.