Wilczek's "Lightness" and other indices Wilczek's "Lightness of Being" gives an up-to-date non-string vision of fundamental physical reality and the ongoing effort to understand it. First published in 2008, it is currently the most visible post-string foundations book for general audience. I keep track of its performance in the market as an indicator of a possible shift in how theoretical physics is perceived by the reading public. The benchmark I use for comparison is the average Amazon salesrank of the five currently most popular stringy books, at noon on the day in question. For example on 10 April the five most popular stringies (elegant, hyperspace, fabric, parallel, warped) ranked 1808, 4069, 4235, 4770, 9452, for an average of 4866.8. Lightness ranked 3540, so it was doing slightly better than par. The ratio was 1.4. The Lightness of Being 1 October 1.9 (2008) 1 November 2.2 1 December 0.8 1 January 0.6 (2009) 1 February 0.4 1 March 0.5 1 April 2.3 10 April 1.4 11 April 1.1 On 11 April, to take another example, the topfive stringies (elegant, fabric, hyperspace, parallel, and elegant paperback) ranked 2294, 2979, 3711, 4374, and 9637 for an average of 4599.0. Lightness ranked 4136. So the ratio was 1.1---Wilczek's book was again slightly above par. It hasn't always done this well. As you can see it experienced a slump, relative to the string benchmark, from around Christmas thru the first of March.