I will explain in my talk how ideas from representation theory can be applied to a solution of a basic "real life" problem. The problem that I will discuss arise in structural biology and concerns determination of the three dimensional structure of a large molecule from the set of images, taken by an electron microscope (3D Cryo Electron Microscopy). Complete solution to this problem will constitute an important scientific breakthrough since it promises to be an entirely general technique which does not require crystallization or other special preparation stages which are present in alternative approaches. The focus of my talk is a particular algorithm which constitutes a basic step for the solution of the 3D reconstruction problem whose main appealing property is its remarkable numerical stability to noise. I will give an introductory explanation of the mathematical principles underlying this novel algorithmic approach, while hinting about how they apply to other related fundamental problems.