An Essay on the Interpolation Theorem of J\'ozef Marcinkiewicz - Polish   Patriot
  In memory of Polish mathematicians murdured by the Soviets and the Nazis.   The total record of accomplishments of Marcinkiewicz in his short life, his talent, perceptions rich in concepts, and technical novelties, go far beyond my ability to give full play within the confines of one article. The importance of Marcinkiewicz's short paper is reflected in the myriad applications and generalizations which earns the right to be called Marcinkiewicz Interpolation Theory   Marcinkiewicz interpolation theorem came after the celebrated convexity theorem of M. Riesz and his student G.O. Thorin. These fundamental works by M. Riesz, G.O. Thorin and J. Marcinkiewicz deal with estimates of the Lp-norms of an operator, knowing its behavior at the end-points of the interval of the exponents p, where the operator is still defined. There are, however, some subtle differences between the Riesz-Thorin and the Marcinkiewicz ideas. Marcinkiewicz approach can be adapted to nonlinear operators, this is what we demonstrate in the present paper. 
Tadeusz Iwaniec
math.AP