This book thoroughly discusses the breadth of self-tracking practices many people partake in toward the end of self-betterment, accountability, or staying on top of one's biology. The author problematizes data-sharing – often without the individual's knowledge – and work cultures that encourage self-tracking for lower insurance premiums that may goad individuals who are uncomfortable with self-tracking to do so in order to save money. For many self-tracking mechanisms, users can't even access and don't own their own data, thereby entering the larger conversation of privacy, surveillance, and compensation. Overall, it's an illuminating book that has made me reconsider my own self-tracking and what kind of data I am inadvertently sharing with third parties.