The Predual and Second Predual of Wa

We identify the predual and second predual of the space Wα. When α = 0,Wα = BMOA. Our results are similar to Fefferman′s and Sarasons duality theorems. The study of boundedness and compactness of Hankel operators on Dirichiet type spaces is the key to our approach. A new result for the Schatten p-class of this operator is also indicated.