Part I. The Research Agenda ; 1. What Is Ecological Rationality? ; Peter M. Todd and Gerd Gigerenzer ; Part II. Uncertainty in the World ; 2. How Heuristics Handle Uncertainty ; Henry Brighton and Gerd Gigerenzer ; 3. When Simple Is Hard to Accept ; Robin M. Hogarth ; 4. Rethinking Cognitive Biases as Environmental Consequences ; Gerd Gigerenzer, Klaus Fiedler, and Henrik Olsson ; Part III. Correlations Between Recognition and the World ; 5. When is the Recognition Heuristic an Adaptive Tool? ; Thorsten Pachur, Peter M. Todd, Gerd Gigerenzer, Lael J. Schooler, and Daniel G. Goldstein ; 6. How Smart Forgetting Helps Heuristic Inference ; Lael J. Schooler, Ralph Hertwig, and Stefan M. Herzog ; 7. How Groups Use Partial Ignorance to Make Good Decisions ; Konstantinos V. Katsikopoulos and Torsten Reimer ; Part IV. Redundancy and Variability in the World ; 8. Redundancy: Environment Structure That Simple Heuristics Can Exploit ; Jorg Rieskamp and Anja Dieckmann ; 9. The Quest for Take-The-Best: Insights and Outlooks from Experimental Research Arndt Broder ; 10. Efficient Cognition Through Limited Search ; Gerd Gigerenzer, Anja Dieckmann, and Wolfgang Gaissmaier ; 11. Simple Rules for Ordering Cues in One-Reason Decision Making ; Anja Dieckmann and Peter M. Todd ; Part V. Rarity and Skewness in the World ; 12. Why Rare Things Are Precious: How Rarity Benefits Inference ; Craig R. M. McKenzie and Valerie M. Chase ; 13. Ecological Rationality for Teams and Committees: Heuristics in Group Decision Making ; Torsten Reimer and Ulrich Hoffrage ; 14. Naive, Fast, and, Frugal Trees for Classification ; Laura F. Martignon, Konstantinos V. Katsikopoulos, and Jan K. Woike ; 15. How Estimation Can Benefit From an Imbalanced World ; Ralph Hertwig, Ulrich Hoffrage, and Rudiger Sparr ; Part VI. Designing the World ; 16. Designed to Fit Minds: Institutions and Ecological Rationality ; Will M. Bennis, Konstantinos V. Katsikopoulos, Daniel G. Goldstein, Anja Dieckmann, and Nathan Berg ; 17. Designing Risk Communication in Health ; Stephanie Kurzenhauser and Ulrich Hoffrage ; 18. Car Parking as a Game Between Simple Heuristics ; John M. C. Hutchinson, Carola Fanselow, and Peter M. Todd ; Part VII. Afterword ; 19. Ecological Rationality: The Normative Study of Heuristics ; Gerd Gigerenzer and Peter M. Todd