Personally, I’m not endorsing the new John Carter movie, which arrived in theaters last Friday. If you like director Andrew Stanton of Finding Nemo and WALL-E fame or have a taste for interplanetary adventures, then maybe it’s worth watching despite the splattering of negative scores that’s currently hitting Rotten Tomatoes. But for me, commercials for the movie rung a too close to Prince of Persia, a mediocre Disney film released in recent years.

Whether or not you plan to frequent the theater soon to see John Carter, you can always download the book it’s based on—and right now the Kindle version of A Princess of Mars, the first in Edgar Rice Burroughs’ science fantasy series Barsoom, is free on Amazon. That’s too good a deal to pass up, especially considering the book’s resounding four-and-a-half star aggregate customer score on the website.

Besides A Princess of Mars and its respective eleven-book series, Burroughs created Tarzan of the Apes, which led to a series of different adaptations, including Disney’s animated production Tarzan in 1999.

A Princess of Mars was previously a direct-to-DVD movie from film studio and distributor The Asylum and has inspired a number of comic books and other appearances, such as a cameo in Alan Moore and Kevin O’Neill’s graphic novel The League of Extraordinary Gentleman.