Answer:
This book is prefaced by the novel The Pilgrim's Progress that is a symbol of how to live as a Christian. In this preface it is included the females character of the book, Mercy, no its male character, so it is a sign that this book is a guide for young girls, it is a guide to get the salvation and the self-improvement.
Alcott wants to emphasize that religion is more important that everyday details of life. The four March sisters have to follow saintly feet and have a spiritual journey through their lives, in spite their situation as "little tripping maids".
