Quantitative trading is a systematic investment approach that utilizes mathematical models, statistical analysis, and automated execution to identify and exploit market opportunities. This chapter examines core quantitative strategies—including arbitrage, trend-following, mean reversion, high-frequency trading, and market-neutral approaches—while analyzing both successful and cautionary cases in the industry. It highlights how quantitative systems extract statistical edges from market data while confronting practical challenges like model risk, regime shifts, and extreme events.