According to the program reviewed in this chapter, people—including experts—use fast-and-frugal heuristics. These heuristics are models of bounded rationality that function well under limited knowledge, memory, and computational capacities. These heuristics are ecologically rational: they are fitted to the structure of information in the environment. While studying experts in the context of this program amounts to modeling them with fast-and-frugal heuristics, studying the acquisition of expertise focuses on how laypeople learn such heuristics. Experts can be viewed as intuitive statisticians. They have larger samples than novices and they are—through experience, education, and feedback—able to construct both accurate models of their environment and smart heuristics. Because fast-and-frugal heuristics do not require complex calculation and are typically easy to set up, this program offers a straightforward way to aid experts: After the heuristics’ performance has been determined under various environmental conditions, experts can be educated about these results.