This document provides an introduction to Unit 2 of the EDUC W200 course, which focuses on how teachers can implement and make best use of technology in the classroom. It discusses the criteria of effectiveness, efficiency, and enhancement (3Es) used to evaluate educational technology tools. Effectiveness means meeting learning goals, efficiency means saving time and resources while coupled with effectiveness, and enhancement means providing engaging experiences and enriching learning environments. Examples of tools that achieve the 3Es include online games, presentation software, and virtual field trips.