I bought this book after my girlfriend left me. To say I was heartbroken is an understatement!
This book helped with the pain - to a degree. I found some of the mental exercises difficult to do and one or two seemed a bit obvious: 'Think over and over of the times your ex annoyed you, and not the times you felt love for them'. OK, I'm simplifying the exercise in question, but you get the idea (and actually that does help!)
It was the main prose in the book that helped me. There is some good common-sense stuff here, that helps you realise your faulty thinking. Especially when it tackles the notion of your ex being 'the only one for you'. It has a very convincing argument (and trust me, I needed convincing) that this line of thought is both true and completely false!
Did it mend my broken heart? No, it didn't. But it did offer some degree of comfort.
If you're reading this, I guess your heart must be broken. Well, your not alone and you have my deepest sympathies. I hope you begin to recover soon.