This document provides an overview of a presentation on return on investment (ROI) in libraries. The presentation covers various topics related to ROI including direct use benefits, indirect use benefits, non-use benefits, cost-benefit methodologies, and challenges in calculating ROI. Examples are given of ROI studies conducted in different types of libraries such as academic, public, special, and national libraries. ROI ranges from 1.02:1 to 31.07:1 depending on the library. Challenges with ROI methodology include a lack of consistency and accurately valuing benefits.