This chapter reviews research using psychometric (correlational) methods and combined experimental-psychometric methods in the study of individual differences in episodic memory. Early individual-differences research was largely atheoretical, conducted within a broader pursuit of the factor-analytic structure of intelligence, and suggested some distinctions among various memory tasks, processes, and abilities, but also some commonalities and general memory abilities. In discussing more recent, theoretically motivated research, we focus on conceptual and empirical distinctions between short-term and working memory as revealed – or not – by individual-differences analyses, including individual-by-treatment interactions that harness the strengths of both correlational and experimental methods.