This review starts with a brief historic outline of the developments in graphite intercalation compounds (GICs) and their predominant application in the field of electrochemical energy systems. The structural outline of ideal GICs and the real irreversible transformations during intercalation/de-intercalation cycles is considered in detail. A general outline of the chemical, electrochemical and the newly introduced photochemical methods for the preparation of GICs is then provided. After a brief discussion of the wide ranging surface analytical tools employed in the characterization of GICs, selected methods of characterization widely employed in the electrochemical context are described with suitable examples. A fairly detailed account of the electrochemistry of donor, acceptor GICs and graphite fluorides which essentially transform into GICs during discharge is also given. Finally, an outline of battery systems that employ at least one intercalated electrode is provided. The scope for further research and development in this area is also indicated.