This document classifies research into three main categories: basic research, applied research, and action research. It also describes strategies for research, dividing them into quantitative and qualitative methods. Basic research aims to develop and refine theory, while applied research focuses on problem solving. Action research involves practitioners studying their own problems. Quantitative research uses statistical analysis and large sample sizes, while qualitative research relies on collecting stories and developing narratives from smaller samples. The document provides examples of studies conducted with these different approaches.