Book excerpt: Exploring Musical Structure is a unique music theory book because it also has an accompanying website for the user to hear hundreds of sound files from the book! This book introduces musical intervals and how they are structured to form scales and chords. You will be introduced to keys and be shown how to change keys in smooth and interesting ways. If you play an instrument that plays chords, like a guitar or piano, this book will help you expand your knowledge of harmony so that you will have a very interesting array of harmonies that you can use, and the content will show you exactly where and how to use them. Would you like to learn how to harmonize a tune? This book shows you how to do this in traditional tonal style. You will be introduced to writing for different instruments. The book also introduces jazz harmonies and takes a peek into modern styles of composition. Musical structure is studied on several levels, from the structure of a single phrase to the form for an entire composition. Need to start at the beginning? That's okay! The approach used in this book begins with foundational principles and concepts and then builds the rest of the content "brick-by-brick" in a logical and natural manner. The information in this book will also help prepare for later coursework or studies in such subjects as orchestration, counterpoint, arranging and composing. Traveling through musical structure is a highly rewarding and fascinating journey. Enjoy the adventure as you explore musical structure!