This workbook is a great addition to help you in your anti-racist work. I say addition because I firmly believe that you need to read/listen/talk more than just this book. Anti-racism is not something you’re ever done learning about. 
The workbook approach is very useful and makes you really critique your own behaviours and thoughts (both conscious and unconscious!). I would have liked to see a little bit more about the places in which race intersects and how we should be working towards a better understanding of those issues. 
All in all, please get this book, and take the full 28 days for it and journal every day, if you’re serious about anti-racism. You need to start reflecting on your own behaviour and socialisation.