All books suggested above are great. There are a lot of books about the old testament out there from real scholars. Start with those that are named "Introduction to ...". Some authors John J. Collins, Christine Hayes, Michael D. Coogan, Frank Moore Cross. It's a world out there. You are going to need few decades to get very deep into the subject of religion, especially the monotheistic religions of the West
Listen to the free lectures of Christine Hayes from Yale. She is very professional and engaging. You will have a better understanding of the Bible without feeling that faith is being attacked.