A good basic investing book is Asset Allocation For Dummies. It covers investment basics such as understanding different asset categories; the relationship between risk and return; the power of proper diversification; understanding the effect of fees, expenses, and taxes on your investments; investing within the context of your lifetime cash flow projection, etc. It also goes beyond the basics and covers topics such as investing in alternatives, real estate, and commodities. It is written in a very understandable format and is a great read for someone new to investing and also for those with experience.