Old and new Euclidean Ramsey theorems.

Mathematics has sometimes been called the science of order. From this point of view, the guiding principle of Ramsey theory is given by the statement, "Complete disorder is impossible. " In a nutshell, Ramsey theory is the study of structure invariant under partitions. In this memorandum we describe an assortment of results from Euclidean Ramsey theory, some classical and some very recent.