From the 33rd (1896) edition onwards hardback copies became available at twice the price of the softback.
The run was limited again to 150 softback sets.
The original publications were in an unusual format (15 cm x 7 cm softback pictorial).
A less expensive binding method is that used for paperback books (sometimes called softback or softcover).
Approximately 150 softback copies were produced of each year from 1864 to 1878 and made available either as part of a set or as singles.
As of early 2014, softback and hardback editions up to and including 1946 have been published.
He introduced a new typeface and new designs for the front covers of both the softback and hardback editions.
Collected volumes have also been produced as both hardback and softback books.