Abstract: Quicksort and quickselect are two fundamental well known algorithms which were invented by C.A.R. Hoare in the early sixties. Their simplicity and elegance, as well as their excellent performance in practice make them the algorithms of choice for sorting and selection in general purpose libraries, system routines, etc. In this talk I'll survey some of the results that I've obtained together with researchers from abroad for those variants of quicksort and quickselect that use samples to choose the pivots, one of the key steps in both algorithms. I'll be briefly describe some of the mathematical techniques that we used, as well as the practical implications of the mathematical analysis.