'The Intelligent Investor'

Legendary investors benjamin Graham in his book "The intelligent investor" stated that stocks become more risky when prices are high and less risky when prices are low.

This we know and is also true when we buy some house hold goods.However while in trading we sell our stocks when prices are falling and when they are rising we feel safe to invest....? Investing is a strange business. A practical wisdom is more of in help than a book warm..I was a book warm..now i do read less and relax more..while relaxing my mind analyse more..in terms of reality. So be a wise pratical trader&thinker in terms of your investments is concerned.