P. G. De Gennes 
Superconductivity Of Metals And Alloys [PDF ebook] 

Drawn from the author”s introductory course at the University of Orsay, Superconductivity of Metals and Alloys is intended to explain the basic knowledge of superconductivity for both experimentalists and theoreticians. These notes begin with an elementary discussion of magnetic properties of Type I and Type II superconductors. The microscopic theory is then built up in the Bogolubov language of self-consistent fields. This text provides the classic, fundamental basis for any work in the field of superconductivity.