Bevis: The Story of a Boy by Richard Jefferies was published in 1882 as a three-volume for adults.
Over the years it came to be seen as a book for children and was the inspiration of for the holiday adventure school of books that I grew up with.
Arthur Ransome's debt to Jefferies is clear, while Malcolm Saville and Denys Watkins-Pitchford even had their own child characters reading Bevis. It had become a touchstone for children's writers.
In 1932 it was republished with the full apparatus of a children's classic: a map on the endpapers and illustrations by E.H. Shepard.
Some critics believe Shepard's drawings for this book are his finest work. You can read a post about them - and see some examples - on The Heroic Age.
When I treated myself to a copy of this book I found this flyer inside it.
Incidentally, if you want a copy of Bevis with Shepard's illustrations then the 1932 edition is the one to go for. In the later editions the printing of them is noticeably less sharp.