The Mathematical Investor, aka Mathematicians Against Fraudulent Financial and Investment Advice (MAFFIA), is a blog, a collection of essays and research papers on financial mathematics.
This site was created out of growing concern with the usage of less-than-fully rigorous mathematical and statistical methodologies in the financial/investment world. [...] Indeed, such statistical errors are likely the primary reason that investment strategies which look good on paper often fall flat in practice.
It's a fairly detailled and also rather caustic look at the world of quants, pseudo-quants and (occasionally) a genuine mathematician. Indeed, a very funny recent article takes a swipe at pseudo-quants for their inability to tell a real trend from noise. Just as a resonator can pick up a frequency from white noise, so pseudo-quants fabricate pseudo-patterns that eventually lead to entropic investment strategies. (Hey! I can write this stuff too!)
Enjoy!