This introduction discusses the importance of studying the world of jinn and devils. While some may think it is a peripheral topic, the author argues it is actually very important since jinn live among humans and aim to misguide them. Billions are spent to search for life on other planets, yet little research is done on these thinking beings that coexist with humans and try to lead them astray. The Quran and hadith provide crucial knowledge about jinn. Understanding them helps humans struggle against Satan's attempts to dominate and destroy them. The book brings together texts and scholars' statements on jinn and devils to help readers understand this topic.