Max Anders is a troll. Obviously one cannot understand the Bible in a mere 30 days, and he admits as much in the intro. Nevertheless, I like this book. In simple, easy-to-understand chapters, he explains the big picture of the Bible. He explains the organization of the Bible books and some basic info on genres of literature. He walks through the entire Bible, giving the meta-narrative, the overall story. He shows how the different books relate to each other chronologically. He also goes through the major doctrines of the Bible.
I think this book, which can read in 30 days (or less), is especially ideal for kids, for new believers, and for people just beginning to study the Bible for themselves. It gives a framework for understanding how everything fits together.
I recommend this book.