Kitab At-Tawhid (Tauhid/Tawheed) is one of the best books on the subject of Tauhid Monotheism and ranks high in authenticity. In this book all the relevant verses of the Qur’an have been discussed reasonably, rationally, and sincerely. The essence of the Qur’an and Sunnah is placed in a very simple manner in this book.
This is the Spanish version of this famous book.