:: Elo calculated ratings before FIDE started using them in 1970 (when Botvinnik was past his peak).  On page 176 of his book, he gives Botvinnik's best five-year average as 2720.  His actual peak must be at least 2720.  On page 89 he shows that peak in about 1946.  Since this is the same system later used by FIDE, I'd put in a note about this - the Elo calculated an unofficial five-year average of 2720, before there were official FIDE ratings.