Burton Malkiel opens A Random Walk Down Wall Street with his foundational, field-defining thesis: short-term stock price movements are essentially unpredictable, following what statisticians term a "random walk," meaning past price patterns provide no genuinely reliable basis for predicting future price movements, directly challenging technical analysis approaches to stock market investing.

Malkiel's foundational argument:

• He presents extensive statistical evidence demonstrating that historical stock price patterns show no genuinely reliable predictive relationship to subsequent price movements, contradicting the underlying premise of technical analysis approaches that attempt to predict future prices based on historical price pattern analysis
• Malkiel argues this random walk pattern emerges naturally from markets functioning with reasonable efficiency — since if predictable price patterns genuinely existed and were exploitable, sophisticated market participants would quickly trade on this information, causing prices to adjust and eliminate the predictable pattern through this very trading activity
• This foundational thesis, while updated with additional supporting evidence across the book's numerous subsequent editions since its original 1973 publication, has remained the book's consistent core argument across several decades and dramatically different market conditions

This foundational random walk premise sets up the book's overall project: examining various investment approaches and strategies against this random walk framework, ultimately building toward Malkiel's practical recommendation for low-cost, passive index investing as the rational response to this demonstrated market unpredictability.