Donald Erik Sarason was an American mathematician who made fundamental advances in the areas of Hardy space theory and VMO. He was one of the most popular doctoral advisors in the Mathematics Department at UC Berkeley. He supervised 39 Ph.D. theses at UC Berkeley.

• Hilbert Spaces Inside Hilbert Spaces. Hilbert Spaces Inside H?. Cauchy Integral Representations. Nonextreme Points. Extreme Points. Angular Derivatives. Higher Derivatives. Equality of H(b) and H(). Equality of H(b) and M(a). Near Equality of H(b) and M(a). Brief Mention of a Few Additional Topics. References. Supplementary References. Index.