Church History: Twenty Centuries of Catholic Christianity by John C. Dwyer was the assigned textbook for my freshman-year theology class, and though it was an excellent textbook, I sometimes wonder how much use it will be for independent study. Church History gives a complete history of the major events in the Catholic Church in 421 pages. Since this is a small space to cover 2000 years of history, the information is not detailed. Most periods of history can be treated only in a cursory manner.
Church History is an excellent resource for understanding the general history of the Church before the Middle Ages and for a brief summary of the medieval Church. However, Dwyer covers the entire Middle Ages in only 33 pages. This is valuable as a quick reference, but since this short space cannot cover medieval social structure, intellectual climate, politics, or cultural relationships, these chapters are too short to be a primary reference for a medievalist.
However, Church History is valuable for the big picture. If one reads the entire book, it is useful to see (in general terms) how the post-medieval reformations help to frame medieval thought and to understand how the modern Catholic Church differs from the medieval Church. Treat this book as an introduction, but for research purposes, look for books that focus on the Middle Ages. The book is written for undergraduate-level work and has an easy, casual style, so it’s not a difficult work to engage with.