Author:
Shaykhِ Abdullah Ibn Jarul-lah (1414H) 
Simple and instructive book explaining Kitab at-Tawhīd as question and answer.
See for example that Shaykh Muhammad ibn al-Hadi Madkhalee says:
Question: Do you recommend the book Al Jami 'Al Farid, comment Kitab At-Tawhid as questions answers of Sheikh Jarullah?
Answer: Yes, it is part of beneficial books, may Allaah have mercy
[http://ar.miraath.net/fatwah/6848]