"One child, one teacher, one book, one pen can change the world." - Malala The diary of a good girl is essentially a textbook or reference guide to help you pass the test that is called 'a happy life'. Written for you by a quirky 17-year-old who just wants to help the world realise good people are different to what they seem. Go ahead and read it, it may be boring at first but bear with me after all not all mathematicians loved maths at the start.