I find that reading the primary religious texts of most religions can be daunting for people interested in exploring different beliefs because the texts often require some form of interpretation or context that newbies won't know (looking at you Lotus Sutra and Mahaparinirvana Sutra). There aren't many religious books that can be read on their own without commentary or additional knowledge and still understand the main principles and beliefs. So if you wanted to teach someone who was interested in learning about your beliefs but couldn't use your main religious text what book would you suggest to them?
I'm interested in basically any religion but would greatly appreciate input from Mahayana Buddhists (especially Tiantai), Pagans, Chinese practitioners of Taoism/Confucianism/folk religion, Muslims, followers of Shinto, and followers of the Baha'i religion.