These notes were written for a course on Ramsey Theory given by the author in Caracas during the first term of 2005. The main objective is to give a self-contained presentation of J. Nešetřil’s proof [Eur. J. Comb. 28, No. 1, 457–468 (2007; Zbl 1106.05099)] that the class of finite ordered metric spaces is a Ramsey class.