You don't have to have read any of Rachel Carson's books in order to fully appreciate the letters she wrote to her best friend. These letters (nearly 3/4 written by Rachel) show the love and intensity of her friendship with Dorothy Freeman; they offer a glimpse of what life was like in the 1950s and 1960s - particularly the world of publishing and environmentalism; they show her fear and courage during her fight with breast cancer. She doesn't go into much detail about the writing process she went through with "Silent Spring," but it's clear that the fact that she wrote it and published it at all is something close to a miracle. Her fight against breast cancer would be an inspiration to anyone. Even with everything that goes on within these letters, what is paramount is her love for Dorothy. Few of Dorothy's letters were saved, but the few that were included in the book show why she and Rachel were such good friends. These letters bring to life many emotions: fear, grief, euphoria, anticipation, dread, anger, confusion, apprehension, appreciation and love.
This book is a narrative of what friendship should be.
Also, the footnotes are absolutely wonderful! Instead of being at the back of the book or at the end of the letters, they are in the margins - so there's no inconvenient flipping back and forth. It's a small detail, but it was one I really appreciated.