1) The Shiller CAPE index is a valuation metric that compares the current stock price to the average inflation-adjusted earnings over the previous 10 years. 2) Currently, US stocks are more expensive than 97% of monthly observations since 1881 according to the CAPE index, suggesting the market is overvalued. 3) While there are arguments that structural changes may justify higher valuations, factors like low interest rates likely explain much of the high CAPE currently. The document recommends diversifying globally and utilizing value investment strategies given the overvaluation concerns signaled by metrics like CAPE and Tobin's Q.