John Gruen ( 1926 - ) is an American painter. John Gruen s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 90 USD for Willem de Kooning with Drink, Watermill, NY, 1961 in 2004 to 1875 USD for Willem de Kooning on Beach with Staff, Water Mill, N.Y., 1959 in 2009 , based on the size and medium of the artwork.