A Comprehensive Guide to Superconductivity discusses the societal and environmental benefits of superconducting devices in electric transportation systems, introducing the electric and thermal characteristics of superconducting devices as well as providing an analysis of their cryogenic systems. The authors describe the main principles of spectroscopic methodology for the analysis of gapped electronic spectra and the electron-boson interaction leading to Cooper pair formation and, in turn, Fermi-sea instability. Additionally, methods to optimize the design of a 2G AC power cable are presented with the goal of providing uniform current distribution among cable layers. Beginning with an introduction to Pauli limited superconducting systems, solid state and ultra-cold atomic gas setups which host the Fulde-Ferrell-Larkin-Ovchinniko superconducting phase are studied, along with relevant experimental diagnostics and reported observations. In closing, the authors discuss the theoretical understanding of Josephson transport in hybrid superconductor quantum dot devices. In particular, Josephson transport is studied through an uncorrelated single-level quantum dot coupled between two Bardeen-Cooper-Schrieffer superconducting leads, modelled by single-impurity Anderson Hamiltonian.