Many forms of media can become dated quite quickly. Even some of the best books, movies and music suddenly lose their luster after a few years whether due to cultural shifts or technological advances. Despite being written in 1937, How To Win Friends and Influence Peopleis not one of those cases.
Written in the middle of the Great Depression and before any of the advances in technology we all take for granted today, Dale Carnegie's book has stood the test of time. I've reviewed quite a few books on this blog and each one I strongly recommend, but if you only read one book I ever review, make it this one.