The idea is simple: just getting a basic introduction to a specific subject is going to require that you read at least three to five books. In the words of my professor, three is good, but five is better.
For instance, let’s say you want to try to understand the war in Vietnam and how it affected the United States. You would have to read Dereliction of Duty by H.R. McMasters, McNamara’s In Retrospect, George Herring’s America’s Longest War, and at least two others. Incidentally, I would recommend reading Hell in a Very Small Place by Bernard Fall and The Last Valley by Martin Windrow for the other two works, as they both focus on the Battle of Dien Bien Phu and the French defeat in Vietnam, providing the background information necessary to understand just how the Vietnamese had already learned how to defeat a technologically superior foe long before the US got involved. The Undetected Enemy by John Nordell, Jr. wouldn’t be a bad choice either, as it deals with an overlooked aspect of the French Indo-China War––namely, how the Eisenhower Administration responded to the French military’s operations.
I’ll also have you not that I’ve intentionally included two books from very different prespectives: Dereliction of Duty by McMasters and In Retrospect by McNamara. If you only read works representing one side of the controversy, you’ll be significantly hobbled when it comes to forming your analysis of the subject matter.
I point this out because it would take at least those five books to have a basic orientation on the matter of the United States involvement in Vietnam. Only after reading at least five works such as those could you begin to speak intelligently about the subject, and even then you would be a long way from any sort of specialist knowledge.
This is why good research skills and a wide knowledge base are so important for pastors. We are expected to be able to speak with authority on homosexuality, yet how many pastors or seminary students have read even one really good work on the subject? Much less three to five, and with at least two of those being from wildly divergent points of view?