What Old Books Still Influence You Today?

I thought about this question as I read over John T.Malloy's book Molloy's Live for success from the early 1980's. If you never read it, it uses research to pinpoint how people become successful. My husband, Glenn, told me that the book influenced him when he was in college and I could see why: it gives clear and concise advice on body signals, how to practice for job interviews and how to communicate verbally and non-verbally with others.

It got me thinking about how important books can be when we read them during our earlier years and apply what we learned as we get older. The works I read in psychology stuck with me through life and I often think of how many of the authors' words and thoughts from time past still hold true today.

What books influenced you in your more formative years and do you still use the information today or does it no longer apply to today's times?