In this book, I try to relieve some of the reticence about trout stream insects that makes many anglers feel inadequate and uneasy. Many excellent books provide very detailed information about specific hatches. But that's not this book's goal. This book is written for new anglers who want a basic understanding of aquatic insects or more seasoned fly fishers who want to take their skills to the next level; those who want to know not only if their flies will work but why they'll work as well. I remember when I was first learning to fly fish, and I read about complicated Latin names or confusing stages of aquatic insect development. I was lost. It was as if the whole fly fishing world was born knowing about these things, and I was left out. This book's aim is to provide basic aquatic insect knowledge that will not only help you to understand more about trout stream insects, but it will also help you catch more trout on your next fishing trip. It will help you to understand why you should tie one fly to your leader rather than another to imitate the hatches you encounter.