The Secret by Rhonda Byrne
This book was a game changer for me! I read it every single day for a month and the change in my mood was incredible. It helped me to recognise that my negative thoughts were only bringing me further negative experiences and it taught me how I could actually control my future experiences way more than I ever knew or could comprehend. Its a great read and I highly recommend it.
The Power of Now by Eckhart Tolle
This book is one of those which you keep and re-read. You can guess from the name what it is about, but it holds so much more than that. This book can be used as a tool by helping you to understand your thinking patterns and how they negatively affect your chance of happiness. It delves into how we very rarely live in the present and mostly live in the pain of the past or in the future which does not exist yet. After reading this you will have a greater understanding of where happiness can be found. A little secret for you: it's not in the past, nor is it in the future... It's in the present only.