Primary sources provide for a glimpse into the thoughts at a specific point in time. However, even primary sources cannot be trusted blindly. Forgeries and after-the-fact editions are unfortunately abundant. The careful study of primary sources from the beginning of writing helps to spot passages that do not fit into a given time.
Primary sources are few and far in-between snapshots of a story long past. They are difficult to understand and could sometimes be interpreted as anything desired. It is like travelling to Egypt, taking just one photograph and then exclaiming that this is what twenty-first century Egypt looked like. Hence, primary sources need to be combined with archaeological findings, with changes in the climate, and with the jet-stream of human thought.
Secondary sources are those that were not produced near the actual times. It seems generally accepted that the story of Judaism and Christianity is riddled with frauds. However, it seems too great a task to spell out what the real tale behind the frauds is. Why was it necessary to commit serial fraud if the history of God and Jesus is clear cut?
The primary sources of Volume II are mainly utilized in trying to unlock the secrets of the establishment of Islam. The approach in The Great Leap-Fraud is that primary evidence is always stronger than later rewritings. Questioning why certain actions were taken brings the reader closer to what the real story may be.
From the fifteenth century forward, secondary sources explode in quantity. Hence, the selection of authors and sources are much more difficult because of bias and conformity to a set of beliefs and expectations. The Great Leap-Fraud is trying to avoid this.
Google Labs at https://ngrams.googlelabs.com is an invaluable Google innovation that lets users enter a search term, returning a graph with number of occurences along a timeline. It will prove all the more powerful once ancient materials will be made available and a term can be defined with syntax variations. While the tool's intention is to trace a word to its origin, it is much more than that. It allows users to trace ideas and cultural trends back to their sources.
Internet Resources
The Internet provides for a vast knowledge pool that must be tapped by researchers. Unfortunately, an increasing number of sites are fee based, restricting future research capabilites. Others are not trustworthy. Users must always double check their Internet resources for authenticity.