Find the number of outcomes in the complement of the given event.
Out of 268 books in a bookcase, 177 are fictional.
The complement of the event "selecting a fictional book from the bookcase" would be selecting a non-fiction book.
There are a total of 268 books in the bookcase, and 177 of them are fictional. This means that there are 268 - 177 = 91 non-fiction books in the bookcase.
Therefore, there are 91 outcomes in the complement of selecting a fictional book from the bookcase.