Harriet Rowland -- known as Hat -- was 17 when she was diagnosed with osteosarcoma, a rare form of cancer that began in her knee. At the time she was a student at Queen Margaret College in Wellington, New Zealand. Going through treatment was often a lonely time, as friends -- while supportive -- didn't always understand Hat's new life. This was until she fell in love with the character Hazel Grace from John Green's novel The Fault in Our Stars, a girl who talks honestly and openly about living with cancer. Like her, Hat found life changed in ways that were both good and bad: falling in love and hospital stays among them. And she was surprised by how much happiness there was still to find. Throughout her journey, Hat has kept a blog called My Experience of Walking the Dog, and this book is a collection of those posts edited with the author. Why the blog title? Her parents say cancer is like a dog -- fine if it stays in its own yard. Hat's dog got out. This is her unexpected story.