Does the stock market overreact? Recent capital market turbulences have cast doubt whether the behaviour of stock markets is in line with rational investor behaviour. This monograph presents a framework to evaluate whether the stock market is in line with underlying fundamentals. This new and revised edition offers an up to date introduction to the controversy between rational asset pricing and behavioural finance. Empirical evidence of stock market overreaction are investigated within the paradigms of rational asset pricing and behavioural finance. Although this monograph will not promise the reader to become a millionaire, it offers a road to obtain a deeper understanding of the forces which drive stock returns. It should be of interest to anyone interested in what drives performance in the stock market.