St Mary's is an Open Church - Open to God, Open to You
Thy Will be Done focuses more or personal spirituality while Living His Story is a more theological discussion. Each is very different in its style of writing and subject matter so one may appeal more than the other, or you might like to tackle both.
Follow one or both books on your own or join in with one or both of the St Saviour's discussion groups on the books - Thy Will be Done, Living His Story. You may well want to read but not take part in the zoom discussion, or just dip in when you feel like it, which is of course perfectly fine! You could even join the discussion without reading the book at all!