Asset management has become central to the development of the financial industry, both in the United States and Europe. The increasing number of cross-border merger and acquisition operations and the extremely high valuations that are put on those operations are evidence of the major financial establishments; desire to invest in a sector that they consider to be essential to their strategy of globalising and "financialising" their activities. Asset management's transition from an "art and craft" to an industry has inevitably called integrated business models into question, favouring specialisation strategies based on cost optimisation and learning curve objectives. Faced with an abundance of tools and academic references, it is important to place all the practices, empirical studies and innovations in their context, given that they are always described as "major" by their promoters in the area of portfolio theory. Portfolio Theory and Performance Analysis - allow the professionals, whether managers or investors, to take a step back and clearly separate true innovations from mere improvements to well-known, existing techniques; puts into context the importance of innovations with regard to the fundamental portfolio management questions, which are the evolution of the investment management process, risk analysis and performance measurement; takes the explicit or implicit assumptions contained in the promoted tools into account and, by so doing, evaluate the inherent interpretative or practical limits