Living in Illinois my entire life, I have had the pleasure of experiencing four seasons in numerous ecosystems throughout the state. This book was inspired by my fascination with the way different ecosystems cope with the changing seasons. Over the past year, I focused on four major ecosystems found in Illinois. I visited multiple sites that represent Prairie and Savanna, Bog, Marsh, and Woodland ecosystems. Through this endeavor, I hope to showcase the beauty of Illinois’ seasonal variation and bring attention to the way specific flora and fauna endure through the seasons. At the beginning of each ecosystem chapter, the flora and fauna featured within the chapter are outlined by season and page number. I invite readers to both learn about the ecosystems represented and appreciate their rich biodiversity.