I felt pretty motivated about reading Esperanto literature, especially after finding the baza legolisto, and thought "I'll cover the basics in a year!". After reading this article I felt a bit floored - and therefore my question how many books there are in Esperanto.
Most of the fiction published in Esperanto consists of translations. If you mean books containing fiction originally written in Esperanto, then there aren't so many: about 200 novels have been published, and 400 volumes of short stories, and some of these books are very short. We are still at the stage at which a very determined person with a lot of money could conceivably read all of them. However, the quality is uneven, so it is a good idea to start with other people's recommendations. Of the novels, about two-thirds date from after 1980. Since then the rate has been about 3½ per year. You can find a detailed list on Sten Johansson's website.
Reading fiction, both original and translated, is a good way to get comfortable with Esperanto. And it is advisable to keep a pocket dictionary on hand to look up words, as that is one of the most efficient methods of expanding vocabulary.
La Katalogo de UEA has about 7461 titles (or 7262, see below), if I managed to count them correctly.
NOTE: It doesn't allow just listing all titles and requires searching by some criteria, so I tried in two ways:
- I first picked titles with price of less than 1€ (361) and then with price of more than 1€ (7100), which makes 7461, assuming there is no overlap or missing titles.
- I selected all titles published after year 1887 (duh), which shows 7262 titles.
In any case, there are more than 7000 books there.
I had read that there was a library of books translated and written in Esperanto by Montagu Butler. His library is listed first in this Wikipedia article of all books/library that are written in Esperanto.