This document provides information about superconductors. It defines key terms like critical temperature (Tc), critical magnetic field (Bc), and critical current density (Jc). It describes the two main types of superconductors - Type I, which has one critical field, and Type II, which can partially exclude magnetic fields between two critical fields. The document then gives a brief history of important discoveries in superconductivity research from 1911 to today. It discusses some applications of superconductors like particle accelerators, generators, and magnetic levitation trains. Finally, it provides details on the YBa2Cu307 ceramic superconductor, its critical parameters, and classification as a Type II superconductor.