The designers of the Linotype machine arranged its keyboard for optimum speed, assuming that the most common letters of English were e,t,a,o,i,n,s,h,r,d,l,u in that order. The Oxford English Dictionary (Second Edition) has some amusing citations:
Knuth, Donald E.
"Etaoin Shrdlu Non-Crashing Sets,"
Word Ways: Vol. 27
, Article 4.
Available at: http://digitalcommons.butler.edu/wordways/vol27/iss3/4