Abstract
On an oriented 3-manifold we can define a contact structure, that is, a completely non-integrable plane field in the tangent bundle of the manifold. Regarding such a structure we consider knots that are everywhere tangent to this plane field. After setting up the basic notions, I am giving an introduction to Legendrian knot theory and briefly present my research topic focusing on two-bridge knots. Sito web: http://people.dm.unipi.it/babygeometri/