This review is based on my recollection of this book some years after reading it, prompted by the Apple TV+ adaptation, which I found to be very faithful, nearly beat-for-beat. This book has stuck with me for years since I first read it- likely because it was one of the last novels I read prior to a period in my life I found myself unmotivated to read much at all. Dark Matter explored the multiverse before it was cool, or at least before I was less excited by stories about it, and as a standalone story it is unburdened by the grandiose typically expected of the topic. This book uses its science-fiction mechanics to tell a therapeutic story about regret and decisions. While the actions taken by the story's characters are not possible in our world, their motivations and emotions feel real. It asks the reader to interrogate their relationship to their own regret. If you had the ability to remake past decisions, not only would you, but would you have the right to? How much of our 'self' is defined by our decisions, experiences, and mistakes? Revisiting the story years later, after the concept of a multiverse has become much more prevalent in popular media, I still find Dark Matter to be captivating. I still find myself regularly inspired by the themes of the book, and it reenters my mind when I feel remorse. I think this book has helped me accept unfavorable outcomes in my life, and forgive myself for my mistakes. And most importantly, it reminds me that these experiences shape me. Wallowing in them inhibits growth, and sometimes repentance is only possible by learning from the past.