THE AMERICAN MAYOR The Best & the Worst Big-City Leaders By Melvin G. Holli Illustrated The Pennsylvania State University Press  210 pages     There are few activities Americans enjoy more than rating things. The historian Arthur Schlesinger Sr. realized this a half-century ago when he canvassed his fellow scholars to rank the nation’s Presidents. Schlesinger’s survey, with its divisions into the Great, Near-Great, Average and the like, spawned several imitators and his own follow-up in 1962. Now Melvin G. Holli, the author of several books on urban politics, has set out to find the country’s 10 best and worst Read More