Book excerpt: How new are the high T c superconductors, as compared to the conventional low T c ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high T c superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high T c oxides for their practical applications? This interesting book aims to provide some answers to those questions, drawing particularly on similarities between the high T c oxides and granular superconductors, which also present a short coherence length and a small superfluid density. Sample Chapter(s). Introduction (86 KB). Chapter 1: Superfluidity (329 KB). Contents: Superfluidity; Coherence Length, Penetration Depth and Critical Temperature; The Phase Transition; Phase Diagrams; Gap, Symmetry and Pseudo-Gap; Basics on Vortices; Cuprate Superconductors Under Strong Fields; From Fundamentals to Applications; HTS Conductors and Their Applications. Readership: Condensed matter physicists, researchers and engineers in applied superconductivity.