Is it possible for a person to be an Islamic thinker, an author, and a telecommunications engineer at the same time? What are the Sharia sciences that must be studied to delve deeply into the Holy Quran? And what should I do about my Christian colleague who raises doubts about the Quran?

We congratulate you on your guidance and commitment, and we advise you to thank Allah, and to utilize your energy in contemplating the Book of Allah and the Sunnah (definition), and to benefit from books of Tafsir (definition) (exegesis), linguistics, and Usul (principles of Islamic jurisprudence). Every Muslim is required to engage with the Qur’an and invite to Allah, and it does not harm if one's academic specialization differs from this. We advise you to postpone dialoguing with the Christian until you are equipped with sufficient Sharia (definition) knowledge to respond to misconceptions, and you can refer him to specialized bodies that respond to Christians.