Eddy currents, so-called owing to their general shape like "eddies", manifest as induced currents in all metallic – magnetic or non-magnetic – regions exposed to time varying or generally alternating magnetic fields whether of power or higher frequencies. It is imperative to apply appropriate analyses to assess the magnitude and consequences of induced eddy currents as required. Therefore, book aims at a comprehensive study of various aspects of eddy currents, from a detailed account of the basic phenomenon to their utilization in various applications, and their detrimental effects, esp. in large Turbogenerators. It gives detailed description of the finite-element technique(s) developed by the author to analyse the steady-state and transient heating of key regions of turbogenerators of ratings from 120 MW to 500 MW when exposed to "negative-sequence" currents under unbalanced fault conditions.