I have always recommended AUTOBIOGRAPHY of a YOGI to everyone I met. Now, adding one more book (as easy to read as for 5th grade student.) to the list "Everything you need to know about Karma" by J.P. Waswani.
(1) The book details importance of omnipotent and omnipresent yet "Subtle law of Karma". ==> Everything happening to you is due to YOUR OWN deeds in past or this life.