A book in Portuguese in which the author shows the fundamentals principles that a Muslim has to know about Allah, Islam, and the Prophet Muhammad. He also shows the types of worship that Allah commanded in a brief and easy explanation.
A useful book translated into Portuguese contains the creed of Ahlu As-sunnah Wal Jamaah with proofs from the Quran and prophetic Sunnah. The author (may Allah have mercy on him) talked about the virtue of monotheism versus the major and minor polytheism.