Question:What is the second most influential book in the world today?
What Old Testament book is the most quoted or referenced to in the New Testament?
Which book of the Bible is thought to be the oldest in terms of when it was written?
"Influential" is a subjective term, so the answer would depend on who you asked.
One list, by Samuel Dawson, that I have shows Psalms being quoted 92 times and Isaiah being quoted 83 times.
The book of Job is believed to have been written contemporarily with Abraham based on some of the references within the book. Depending on who you wish to read the phrases in Genesis, there are 11 places where it states "these are the records of." The book of Genesis is attributed to Moses, but quotes from Genesis are never called the words of Moses. Some conclude that Moses served as editor for a set of earlier records, either preserved by the lineage or given to Moses by the inspiration of the Holy Spirit. Since one of the records is the records of Adam, it can be claimed to be the oldest section of our Bible even though it is only a portion of a book.