How can one respond to the misconceptions concerning the existence and prophethood of Prophet Muhammad, the Quran being the Book of Allah, the descent of Gabriel upon him, and the veracity of those who transmitted the Quran and Hadith, and what are the books and sources that help in responding to the misconceptions of atheists and Christians?

The questioner must differentiate between the domain of issuing fatwas and the domain of scientific research. What the questioner seeks is not appropriate for the domain of fatwas. The doubts mentioned have been briefly addressed in previous fatwas. The questioner can find what he is looking for in specialized references and websites dedicated to refuting people of whims and sects, such as the comprehensive doubts file on (Al-Kashif website). Further information can be obtained by referring to Fatwa no. 41069.