It would be the most crucial day of the entire war.
There are innumerable writing problems in an extended work. One book took a little more than six years. You, the writer, change in six years. The life around you changes. Your family changes. They grow up. They move away. The world is changing. You're also learning more about the subject. By the time you're writing the last chapters of the book, you know much more than you did when you started at the beginning.
I could not do what I do without the kindness, consideration, resourcefulness and work of librarians, particularly in public libraries... What started me writing history happened because of some curiosity that I had about some photographs I'd seen in the Library of Congress.
When you start to write, things begin to come into focus in a way they don't when you're not writing. It's a very good way to find out how much you don't know because you learn specifically what you need to know that you don't know at the moment by writing.
Nothing ever invented can you a bigger life than a book.