So it’s summer, which means that maybe you’ve got some free time on your hands. Maybe you’re even really lucky and will be spending some of that time on the beach, or by the pool. Maybe it’s the kind of free time that can really only be filled by taking a serious nosedive into an epic book series that will eat your life until you’ve finished it. Well if science fiction is your cup of tea, here are some of my favorite series. Though if you get sucked in and neglect the rest of your life, don’t blame me!

Saga of the Skolian Empire, by Catherine Asaro

I once heard someone call these books “science fiction for girls,” which is pretty silly in my opinion – but there aren’t that many series that combine hard science fiction with romance, and Asaro does an amazing job in these books. And if you are a fan of hard scifi, especially in the form of physics and biotechnology, don’t doubt Asaro’s cred just because she sneaks in the romantic entanglements – she has a PhD from Harvard and was a physics professor before she started writing full time. The Skolian books are essentially space opera, heavy on the political intrigue, artificial intelligence, and interstellar travel – also strong female characters. The first book in the series by publication is Primary Inversion, but you can also read them in chronological order.

The Night’s Dawn Trilogy, by Peter F. Hamilton

I read these books perhaps a decade ago, and they were my first real foray into space opera – which is really like jumping in headfirst. Though it’s technically a trilogy, the paperbacks were published in two parts for each book – and they were still pretty thick, so trust me when I say that this series still counts as “epic.” The world here is so sprawling that it’s hard to describe the books briefly, but the gist is that it’s a far-future with tension between users of biotechnology and nanotechnology – oh, and a little problem with souls of the dead coming back through living possession. Even though this future is ostensibly a “golden age,” the story of the Night’s Dawn books is still very much about the darker side of humanity. Most people I know who’ve read these either love them or hate them, so be prepared. The first book is The Reality Dysfunction.

The Ender’s Game Series, by Orson Scott Card

Now here’s a no-brainer. If you didn’t read the first book as a kid, now is the time to pick it up – along with the follow-ups. And if you did read it as a kid, it’s the sort of thing you want to try again as an adult, especially if you didn’t get through the entire series. Battle School is just the beginning of the story, and Speaker of the Dead is no children’s book. Again, with a 3000-year span of time over the course of the series, you can always try reading them in chronological order. Though I think I’d still recommend starting with Ender’s Game.

The Dune Novels, by Frank Herbert (and progeny)

I’m not really sure what to say about Dune… I feel like if you’re interested in the idea of reading science fiction series at all then surely you’ve already read these books. These are some of the most influential books in the genre, considered a landmark of world-building and “soft” science fiction (i.e., not focused on technology). The “originals” are of course the first six, from Dune to Chapterhouse: Dune, though after Frank Herbert’s death, his son Brian along with author Kevin J. Anderson have added a number of books to the series. If you really want to take on an epic reading task for the summer, you could try reading the entire franchise in chronological order. Or you could just be traditional and start with Dune.

The Time Quartet, by Madeline L’Engle

You’ve probably read A Wrinkle in Time. If you haven’t, then turn off your computer and go get a copy right this instant. But even if you have, I just want to be sure that you appreciate the true epic nature of the story by reading all of the books tied to it as well. The “quartet” – consisting of A Wind in the Door, A Swiftly Tilting Planet, and Many Waters as well – isn’t even the end of the story. An Acceptable Time, focusing on a child of the next generation, is considered an official follow-up – but there are other connected books as well, such as The Arm of the Starfish. L’Engle is one of those authors whose worlds tend to touch each other all over the place, but at the very least, the eight books about the Murrays and the O’Keefes are the heart of the story. Though to take the epic journey through time travel, biology, and saving the world from evil, you’ll still need to start with A Wrinkle in Time.

Five is actually a pretty short list as far as these things go, and I know that you guys must have more to recommend. So for the benefit of our other readers, comment with your favorite epic scifi series! Or tell us what’s next in your reading queue for the summer. And for your fantasy fans, you’re also in luck, because there might be another post like this coming soon.