Discover the enchanting San Bruno Mountain, a vital ecological preserve nestled in the heart of the San Francisco Bay Area. Celebrated as a global biodiversity 'hot spot,' this four-square mile gem is a rare natural treasure that offers an invaluable glimpse into the region's rich flora and fauna before colonization. In this comprehensive field guide, co-authors Doug Allshouse and David Nelson reveal the mountain's hidden wonders through years of scientific research, observations, and personal journeys. With over 528 documented plant species, including 316 native varieties, readers will engage deeply with the unique ecosystems found on San Bruno Mountain. The guide also explores the fascinating history that has shaped this living environment at the southern edge of San Francisco, detailing the myriad birds, butterflies, and reptiles that inhabit the area, alongside insights into its geology and climate. Ideal for nature enthusiasts, conservationists, and local hikers alike, this book is not just a field guide, but a celebration of the remarkable biodiversity and importance of San Bruno Mountain. Uncover the stories and species that thrive here and understand the tireless efforts of conservationists who worked to preserve this wild sanctuary we cherish today.