Springer sale

Springer Verlag is having a sale on mathematics books through the end of July, offering "many essential mathematical titles" for half price. So you can snap up Alpay and Vinikov's Operator Theory, Systems Theory and Scattering Theory: Multidimensional Generalizations for a mere 64,90€ instead of the normal price of 129,00€, thereby achieving a saving of 64,10€, or 49.69%. Also many other great and somewhat more affordable items, all here.