Chapter 1. Risk matrix: Foundations and Overview.- Chapter 2. Different types of risk matrices and typical applications.- Chapter 3. Rating scheme design methods.- Chapter 4. Risk perceptions in risk matrix: sources and impact to risk matrix design.- Chapter 5. Risk matrix design assessment: criteria and quantitative indicators.- Chapter 6. Risk matrix aggregation: A general framework.- Chapter 7. Risk matrix aggregation methods: introduction and comparative analysis.- Chapter 8. Three dimensional risk matrix: theoretical basis and construction. Chapter 9. Conclusion.