Aubrey Williams has a fine treatment (115) of the second 
Dunciad  of 1729 in which he quotes Pope’s own words to 
Swift:

     The Dunciad is going to be printed in all pomp. . . . It will 
     be attended with Proeme , Prolegomena , Testimonia  
     Scriptorum , Index Authorum , and Notes Variorum . As to 
     the latter, I desire you to read over the text, and make a few 
     in any way you like best, whether dry raillery, upon the style 
     and way of commenting of trivial critics; or humorous, upon 
     the authors in the poem; or historical, of persons, places, 
     times; or explanatory; or collecting the parallel passages of 
     the ancients.

Instead, that is, of a mere individual book attack on Dulness, 
Pope has provided a collective newspaper format and