This second edition effectively prepares education students, elementary or secondary school teachers, or college instructors to teach geometry. It can also serve as a useful reference for anyone in these fields. This book can also serve as a textbook in an elementary plane geometry course having an investigative emphasis. The text explores geometric concepts inductively first and then presents deductive proof. Students are encouraged to explore geometric ideas using constructions, laboratory materials, and various other investigative techniques. The text promotes student interaction by emphasizing small group investigation. This edition helps teachers implement the latest NCTM standards by addressing the development of critical thinking, the use of technology to explore geometric relationships, the use of geometry as a medium for problem solving, and the importance of applications in geometry.