If you're asking about the novel titled 'Ernest', that question is sneakier than it looks. There isn't a single,
famous novel universally known just as 'Ernest' the way there is for, say, '
Dracula' or '
1984'. The name 'Ernest' is most often associated with the writer Ernest Hemingway, who authored classics like '
The Old Man and the Sea' and '
A Farewell to Arms', but those books are not titled 'Ernest'. It's also easy to mix things up with 'The Importance of Being Earnest' by Oscar Wilde — note the different spelling — which is a well-known play rather than a novel.
Another route people take is thinking about the character Ernest P. Worrell, created by John R. Cherry III and played by Jim Varney in films and TV; that character spawned movies and tie-ins, though not a canonical standalone literary novel that everyone points to. There are, of course, modern indie or small-press novels that could be titled 'Ernest'—small presses sometimes publish single-name titles—so if you spotted a contemporary book with that title, checking the cover or metadata will reveal the author.
all in all, if you meant a classic author, you were probably thinking of Ernest Hemingway; if you meant the title with ‘Earnest’, that’s Oscar Wilde’s play. If it’s a niche or indie novel titled 'Ernest', the author could be anyone, but the title itself isn’t tied to a single celebrated novelist in the way you might expect. Hope that clears up the confusion—I always enjoy these little literary puzzles.