The problem I have with this advice is that its all based on the last 50 years which have been absolutely incredible returns for investors. You should also read more history of what happened to Japanese property investors in the 90s, Argentinian investors in the 70s and Russian/Chinese/Cambodian capitalists before their communist takeovers.
I read a few of the books mentioned in the article (Random Walk, Common Sense, Global Value and Asset Allocation) and they certainly dedicate a lot of space to study the history: bubbles, how returns fluctuated over the decades, etc.
Most importantly, the key takeaway of those introductory books is to diversify your portfolio, which, if you do, should limit your losses in events such as those you mention.
