Book stores and various vendors want to kw what genre a book is so they can place it on a shelf making it easy for those wanting a specific type book. The Mysterious Envelope could be classified as a fictional mystery. The characters and events are imaginary, but the cities are real. Furthermore, it could be defined as Christian fiction, since God's involvement is scattered throughout the story. This removes the book from being entirely fictional. The hypothesis of the book was written by a pastor that spent nearly fifty years teaching and encouraging folks to trust God. You should be forewarned, however, there are scenes and language that could be offensive to some. Edna is a widowed, devout Christian, mother struggling to raise two sons during the depression years. The two boys have very different personalities and outlooks on life, making the mother's conflict more difficult. Her faith is severely tested and many times events appear hopeless. Twists and turns in the road the sons travel makes reading interesting, as you feel the heartache the mother endures. There are scenes where the Word of God explains why trouble occurs in most anyone regardless of circumstance. I trust that anyone reading this book will find hope and encouragement.