The development of intellectual capital theory has been guided by the ideas and thoughts of a handful of influential practitioners, including Karl Erik Sveiby (1997), RS Kaplan (Kaplan and Norton, 1992) and Leif Edvinson (Edvinson and Malone, 1997). These pioneers established the basis of the "intellectual capital standard theory". In the present paper the assumptions and principles that support the standard theory (the prevailing paradigm) are discussed. The paper then introduces other models and methodologies as alternatives to the standard theorysuch as the "IC Accounting System" (Mouritsen et al., 2001), the "Value Explorer" (Andriessen and Tissen, 2000) and the "Intellectual Capital Benchmarking System (ICBS)" (Viedma, 2001)and examines the foundations and principles on which the alternative new theory (the 'new paradigm') is based. Finally, the paper attempts to synthesise both of these theoretical approaches with other new views and contributions, and tries to develop the basis for a first general theory of intellectual capital.