Memoirs are important for many reasons, but possibly he best reasons for writing a memoir are:
1. They are therapeutic. Many people write memoirs to help themselves put a tragedy or other story into perspective and help them to relate to other people.
2. Writing memoirs helps a person tell their story the way they perceived it, whether or not it is "True". Truth for the writer pertains to how they FEEL about the situation they are writing about more than how the actual events take place.
3. Memoirs are a personal sharing of life experience.
Memoirs are not always a true story. Sometimes they can be fictional, used to convey the emotions they are experiencing. (See the book "The Things They Carried" by author Tim O'Brien). This book is considered a memoir though it is a fictional story about a non-fictional war.
Possibly the main purpose for writing a memoir is simply to tell the story from the author's perspective, which is of course the first person perspective instead of the broad view that we get from something like a history book. The personal perspective is more accurate because it shows what happens to the person physically, emotionally, and psychologically, which is the best way to understand a story.
In "Civil Disobedience," Thoreau championed the idea that if a government is not going to improve itself, then it is the duty of the people to refuse to support it. This paved the way for non-violent protests, such as those led by Gandhi and Martin Luther King, Jr
