The rapid growth of hedge funds in recent years has been accompanied by cases of severe failure. Since the aftermath of Long Term Capital Management (LTCM), investors recognize that hedge funds may provide high expected returns but they might be exposed to a huge downside risk that is not easily detected by traditional risk measures. My dissertation consists of three essays on the risk of hedge funds. In the first essay, I use a cross-sectional approach to analyze the risk-return trade-off. I compare semi-deviation, value-at-risk (VaR), Expected Shortfall (ES) and Tail Risk (TR) with standard deviation. Using the Fama and French (1992) methodology and TASS data, I find that the left-tail risk captured by Expected Shortfall (ES) explains the...