This collection brings together foundational research on how people make judgments under uncertainty, conducted primarily by Daniel Kahneman and Amos Tversky in the 1970s. Their work demonstrated that human judgment relies on cognitive shortcuts—heuristics—that are efficient but systematically biased. People judge probability by how easily examples come to mind (availability), how representative a case seems (representativeness), and by adjusting from an initial value (anchoring). These heuristics produce predictable errors: we overweight dramatic events, see patterns in randomness, and are fooled by how questions are framed. The collection includes Kahneman and Tversky's original papers plus contributions from other researchers extending their framework. This research launched behavioral economics and has influenced fields from medicine to law to public policy. Kahneman won the Nobel Prize in Economics in 2002; Tversky died in 1996 and would have shared it. For readers interested in human cognition and decision-making, these papers remain essential primary sources. The writing is technical but accessible to patient readers, revealing how our minds work and why we so often get things wrong.