Curriculum integration, while a commonly used educational term, remains a challenging concept to define and examine both in research and in classroom practice. Numerous types and definitions of curriculum integration exist in educational research, while, in comparison, teachers tend to focus on curriculum integration simply as a mixing of subject areas. To better understand curriculum integration in practice, this book details a case study that examines both teacher and student perspectives regarding a secondary school integrated unit on energy. The unit is comprehensively described, the teacher perspectives are examined, and the student perspectives and learnings are explored. This book illustrates the importance of examining why teachers choose to implement an integrated unit, the planning and scheduling challenges that exist, and the complications inherent in trying to identify any impact on student learning. For teachers looking to implement curriculum integration in their own practice and researchers examining curriculum integration, this book provides details, examples, and problems for consideration.