Martin Fowler Books

UML Distilled: A Brief Guide to the Standard Object Modeling Language
Patterns of Enterprise Application Architecture
Refactoring to Patterns
Refactoring: Improving the Design of Existing Code
Analysis Patterns: Reusable Object Models
NoSQL Distilled: A Brief Guide to the Emerging World of Polyglot Persistence
Domain-Specific Languages (Addison-Wesley Signature Series