The book is motivated by the disruptions introduced by the financial crisis and the many attempts that have followed to propose new ideas and remedies. Assembling contributions by authors from a variety of backgrounds, this collection illustrates the potentials resulting from the marriage of financial economics, complexity theory and an out-of-equilibrium view of the economic world. Challenging the traditional hypotheses that lie behind financial market functioning, new evidence is provided about the hidden factors fuelling bubbles, the impact of agents’ heterogeneity, the importance of endogeneity in the information transmission mechanism, the dynamics of herding, the sources of volatility, the portfolio optimization techniques, the financial innovation and the trend identification in a nonlinear time-series framework. Presenting the advances made in financial market analysis, and putting emphasis on nonlinear dynamics, this book suggests interdisciplinary methodologies for the study of well-known stylised facts and financial abnormalities. This book was originally published as a special issue of The European Journal of Finance.