Cover Image by Steve Oudot (INRIA, Sophia Antipolis) The standard left trefoil knot, represented as the intersection between two algebraic surfaces that are the images through a stereographic projection of two submanifolds of the unit 3-sphere S3 – further details can be found in [1, Chap. III, Section ]. This picture was obtained from a 3D model generated with the CGAL surface meshing algorithm. [1] E. Brieskorn and H. Knörrer. Plane Algebraic Curves. Birkhäuser, Basel