This book is basically what you might expect of a diary. But for anyone interested in the historical development of early Baptists in America (or American religious history more generally), this book is a wonderful panorama of first-hand knowledge of the facts, characters, and experiences.
If you happen to be a historian and a local church pastor, then you will appreciate this diary all the more. As I read Backus candidly express his pastoral misgivings and longings, as I read about heartbreaking as well as joy-filled episodes in the lives of everyday people, and as I read about the unfolding of providence in the activities of one pastor and one local church (those that rippled far beyond these singular players), I was encouraged and edified concerning my own ministry today.
I highly recommend this book for the reasons stated above, but it is a long and tedious read. If you don't open it with a pretty keen interest in the subject already, and if you don't know how significant Backus and FBC Middleborough was/is, then you can still gain from the book. But you probably won't enjoy it before doing some hard work in reading to understand it.