Sci-fi fans have probably read most of the most famous and popular titles—but there are tons of lesser-known books that are just as amazing. Tom Merritt runs through his list of top sci-fi hidden gems.

From the list:

When looking for a good sci-fi book, most of us don’t need to be told the classics. Dune, Foundation, Neuromancer—you already know those and most likely have read them. The true gold is in the books someone tells you they read and loved and yet you have never heard of them. That’s where you find the gems. So with a small hope that maybe you can find a couple of gems here, I present my top 26 most underrated science fiction books.

1. Clans of the Alphane Moon by Philip K. Dick
You think you know Philip K. Dick because you’ve seen Total Recall, Blade Runner, and Minority Report, right? I submit that you don’t really know Philip K. Dick until you read this book set on a planet that is also a mental institution where clans have arisen centered around their diagnosis. It features a slime mold named Lord Running Clam.

2. The Sparrow by Mary Doria Russell
Sometimes people ask what would happen if the Jesuits led space exploration. No, seriously, sometimes people ask that. And when they do I tell them to read The Sparrow.

3. Stories of Your Life and Others by Ted Chiang
Not enough people saw the movie Arrival, but those who did loved it. Even fewer read the source story that is the title of this collection—and it may not even be the best of the nine stories collected here, which includes three Nebula Award winners, one of which also won a Hugo.

4. Blue Remembered Earth by Alastair Reynolds
Here’s an optimistic future in which humanity has begun to repair the Earth and explore the stars. It includes one of the most interesting devices to overcome the speed of light delay in long distance communications that I have ever read.