- A Tale of Two Cultures: Qualitative and Quantitative Research in the Social Sciences
- Social Science Concepts and Measurement: New and Completely Revised Edition
- Explaining War and Peace: Case Studies and Necessary Condition Counterfactuals (Contemporary Security Studies)
- The Puzzle of Peace: The Evolution of Peace in the International System
- Multimethod Research, Causal Mechanisms, and Case Studies: An Integrated Approach