What are the forbidden books? What is the ruling on the novel "The Turban and the Cap"? What are the regulations for reading foreign books? And is it permissible to read for a Christian author on non-religious matters?

It is more befitting for a Muslim to read what benefits him in his religion and worldly life, such as books of Tafsir (exegesis), Hadith (prophetic traditions), and Fiqh (jurisprudence), and to avoid books that contain innovations (bid'ah), disbelief (kufr), violations of Islamic law, or incitement to vice. There is no harm in reading books by disbelievers if they are beneficial and do not contradict Islamic law, provided the reader can distinguish between what violates Islamic law and what does not.