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Liberty Hardy is an unrepentant velocireader, writer, bitey mad lady, and tattoo canvas. Turn-ons include books, books and books. Her favorite exclamation is “Holy cats!” Liberty reads more than should be legal, sleeps very little, frequently writes on her belly with Sharpie markers, and when she dies, she’s leaving her body to library science. Until then, she lives with her three cats, Millay, Farrokh, and Zevon, in Maine. She is also right behind you. Just kidding! She’s too busy reading. Twitter: @MissLiberty

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Books, like readers, come in many varieties. There are books that you read to be scared, to swoon, to laugh. Some books are designed to be comfortingly cozy, and are for low-maintenance reading. And some are complex, intricately plotted novels, with multiple storylines, complicated technology, elaborate systems of government, or a large cast of characters. And some have all those things in one book!

Those kinds of books can be called “brain-on” books, a term likely coined on the Internet by book enthusiast @mynameismarines, meaning you have to really give them your full concentration. Some readers may find brain-on books confusing or hard to follow, while others may not. There’s no judgment if you do—everyone’s brain is different.

And it doesn’t mean that if you have to work harder to read a book, that it is any better or worse (or smarter) than books that you don’t. Reading tastes are subjective! This is just a post in appreciation of a few great SFF novels that could be considered “brain-on” books, for various reasons. Pick one up when you’re in the mood to really stimulate your brain pan!

Piranesi by Susanna Clarke

In this dark fantasy, Piranesi resides in a surreal building, where the tides go in and out, flooding its halls, and statues surround him on all sides. In this world, Piranesi would be lonely, but he enjoys his time exploring his building. And The Other pays him a visit twice a week to discuss secret knowledge. But as time goes by and he explores further, a new person appears, changing everything Piranesi knows and the fabric of his existence itself.

The Fifth Season by N.K. Jemisin

This is a monumental start to a three-time Hugo award-winning trilogy! It starts with a woman named Essun, who is searching for her missing daughter as the world braces for a terrible climate event, known as the Fifth Season. Essun’s journey is fraught with peril, as people like her, the Orogenes, are feared and oppressed because of their abilities to control the geological forces of the world.

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Ninefox Gambit by Yoon Ha Lee

In this exciting military space opera, a disgraced captain is given a second chance, but it comes with a high price. Captain Kel Cheris is grateful that Kel Command has decided to take one more chance on her and give her a new assignment. She is to capture the Fortress of Scattered Needles back from the heretics. Complicating matters is undead tactician Shuos Jedao, who might be able to offer Cheris her best strategy for retaking the fortress. But he also went mad and massacred a bunch of people in his first life, so she has that possibility hanging over her mission, as well as the fear of failure. (There’s a shiny new tenth anniversary edition of this novel coming in May 2026!)

Middlegame by Seanan McGuire

Roger and Dodger are brilliant twins, with minds able to comprehend things humans can’t imagine. That’s because they’re not human, but they don’t know that. They were actually created by an alchemist named Reed, who hopes to raise the twins to be the most powerful beings in the universe and then claim their power as his own. But how will the twins feel about it when they discover his nefarious plans?

There Is No Antimemetics Division by Qntm

This novel is a success story like The Martian, or Dungeon Crawler Carl, where it was originally self-published and became so popular, it landed a deal with a traditional publishing house. It’s based on the idea of antimemes, or information that discourages its own sharing or is opposed to being shared. In this novel, people are forgetting information as soon as it is shared, stolen away by hidden enemies they can’t remember exist.

Down in the Sea of Angels by Khan Wong

And last, but not least, this recent dystopian fantasy that follows three time lines involving individuals who are linked to each other through psionic (I had to look it up) or psychic abilities. In 2106, Maida Sun is able to garner the history of an object through touch, which connects her with a tech designer in 2006 and a sex-trafficking victim in 1906. Maida will need all the information from the past she can find to help her stop a politician who plans to round up all the psychic people and take their powers for himself.

Okay, star bits, now take the knowledge you have learned here today and use it for good, not evil. If you want to know more about books, I talk about books pretty much nonstop (when I’m not reading them), and you can hear me say lots of adjectives about them on the BR podcastAll the Books! and onInstagram.