The Bible. I pretty much read it every day. I think it was C.S. Lewis who talked about chronological snobbery i.e. we think we are cleverer than those who went before us. It amazes me that many of the issues we have are the same as issues people had thousands of year ago.

Two days ago one of my children was caught out telling a lie. The next morning my daily bible reading for that day was from Proverbs about the importance of not telling lies. As I say, some things don't change :-)