"As I learned all too well, brain health isn't an 'us versus them' situation. Every one of us has the capacity to suffer in this way, and most of us - at some time in our lives - will. We teach our kids the importance of good dental care, proper nutrition, and financial responsibility. How many of us teach our children to monitor their own brain health, or know how to do it ourselves?

I did not know, and the greatest regret of my life is that I didn't teach Dylan."

This was a harrowing and brave book. This wasn't an easy read. In it, Sue Klebold, mother of one of the Columbine shooters, tells of her grief, horror and shame, as she tries to work out why her son came to carry out one of the worst shootings in US history. It has reshaped how I think of the families of murderers. Dylan was clearly beloved by his family and well-cared for. Klebold explores his behaviours in the run-up to the tragedy - behaviours that, at the time, she did not realise were indicators of depression and mental illness. She now works as a suicide prevention activist. At no point does she excuse Dylan's crimes - and indeed much of the book focuses on the anguish and suffering of his victims. However, ultimately, the truly frightening message of this book is that Dylan was no "monster": he was an ordinary teen, who became profoundly unwell, with devastating consequences.

All profits from the book are donated to research and to charitable organisations focusing on mental health issues.