Since being popularised by Goleman's (1995) best-seller by the same name, Emotional Intelligence (EI), as a construct, has permeated circles in both lay and academic psychological communities. This construct has been broadly applied to address health, education, and business concerns. An in-depth examination of EI research, however, suggests some concerns regarding this construct. In particular, a great deal of variety exists regarding how EI is best conceptualised and measured. The current volume is designed to address measurement issues regarding EI in a multi-faceted manner. The work presented here provides the interested reader with broad, in-depth, and critical perspectives on (a) how EI is best measured, and, by extension, (b) what EI really is.