Dear colleagues, 
 
I am writing a chapter now and I remark that Henry George's Progress and  
Poverty was one of the top N best sellers in economics ever.  I think that is true  
but (a) I have no idea what numerical value to assign to N, (b) am I  
excluding Samuelson's Principles and/or should I be excluding Samuelson's Principles,  
and (c) what are the N-1 other best sellers I should include on that list? 
 
I think this question is directly relevant also to Bob Heilbroner's passing  
and our appreciation to him for his Worldly Philosophers.  Should the Worldly  
Philosophers be on my list along with Progress and Poverty? 
 
Also, if we assume that data gathering is free and instantaneously available,  
what quantitative criteria should be use to rank texts as "best sellers." 
 
Best wishes, 
 
Laurence Moss