Best Sci Fi Books Public Domain: 5 Picks Compared

The best sci fi books public domain readers can download are the genre’s founding works, free because their copyrights expired. We compared five editions by edition quality, author standing and length, using only what each listing publishes. Wells’s time travel classic in an enriched edition leads, followed by two Burroughs Mars adventures.

ShelfAnswers earns a commission when you buy through links on this page, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Affiliate disclosure.

The picks

#	Product	Shelf Score	Buy
1	The Time Machine by Wells	9.7/10	Buy on Amazon
2	The Gods of Mars	9.6/10	Buy on Amazon
3	Warlord of Mars	9.6/10	Buy on Amazon
4	The Skull by Dick	9.5/10	Buy on Amazon
5	The Colors of Space	9.5/10	Buy on Amazon

1

The Time Machine by Wells

H. G. Wells·9.7/10 Shelf Score

i

The Shelf Score runs from 9.2 to 9.8 and weighs fit for the reader or goal (35 points), contents and edition (25), value (25) and listed reading age or level (10, where the listing gives one), using only what the book listing states. How we pick ›

Wells's time travel novella in an Enriched Classics edition, the genre's founding work.

Check price on Amazon

Pros

• Time travel classic stated
• Enriched Classics edition stated
• Founding sci fi work stated

Cons

• Length is not stated
• Enriched edition, not a bare text
• No certification is stated

2

The Gods of Mars

Edgar Rice Burroughs·9.6/10 Shelf Score

i

The Shelf Score runs from 9.2 to 9.8 and weighs fit for the reader or goal (35 points), contents and edition (25), value (25) and listed reading age or level (10, where the listing gives one), using only what the book listing states. How we pick ›

Burroughs's Mars adventure as a 402 KB volunteer Kindle conversion, free on the web.

Check price on Amazon

Pros

• Burroughs Mars adventure stated
• 402 KB stated
• Free on the web stated

Cons

• Volunteer conversion, not enriched
• File size only, no page count
• No certification is stated

3

Warlord of Mars

Edgar Rice Burroughs·9.6/10 Shelf Score

i

The Shelf Score runs from 9.2 to 9.8 and weighs fit for the reader or goal (35 points), contents and edition (25), value (25) and listed reading age or level (10, where the listing gives one), using only what the book listing states. How we pick ›

The Mars sequel as a 327 KB volunteer Kindle conversion, free on the web.

Check price on Amazon

Pros

• Burroughs Mars sequel stated
• 327 KB stated
• Free on the web stated

Cons

• Volunteer conversion, not enriched
• File size only, no page count
• No certification is stated

4

The Skull by Dick

Philip K. Dick·9.5/10 Shelf Score

i

The Shelf Score runs from 9.2 to 9.8 and weighs fit for the reader or goal (35 points), contents and edition (25), value (25) and listed reading age or level (10, where the listing gives one), using only what the book listing states. How we pick ›

Philip K. Dick's 37-page short story as a volunteer Kindle conversion.

Check price on Amazon

Pros

• Philip K. Dick stated
• 37 pages stated
• Free on the web stated

Cons

• 37 pages, a single sitting
• Volunteer conversion, not enriched
• No certification is stated

5

The Colors of Space

Marion Zimmer Bradley·9.5/10 Shelf Score

i

The Shelf Score runs from 9.2 to 9.8 and weighs fit for the reader or goal (35 points), contents and edition (25), value (25) and listed reading age or level (10, where the listing gives one), using only what the book listing states. How we pick ›

Marion Zimmer Bradley's space novel as a 237 KB volunteer Kindle conversion.

Check price on Amazon

Pros

• Marion Zimmer Bradley stated
• 237 KB stated
• Free on the web stated

Cons

• Volunteer conversion, not enriched
• File size only, no page count
• No certification is stated

As an Amazon Associate I earn from qualifying purchases.

More picks to compare

• Masters of SpaceEvans, space operaCheck on Amazon
• Science Fiction Short Storiesshort story collectionCheck on Amazon
• The Space RoverSloat, space adventureCheck on Amazon

Compare the picks

Book details as published on each listing, collected 20 October 2026.

How we scored them

The Shelf Score weighs edition quality, author standing and length from the listings. None of the five state a warranty or certification, which is normal for books. How we pick explains the weights.

Scores run from 9.2 to 9.8: each book’s point total is placed on that range, so more points always means a higher score. Reading age or level counts on a list where at least one listing gives one, and a book whose listing gives none then scores zero on it. Where no listing gives one, the score is taken over the other 85 points. Books carry no warranty, so warranty is not scored.

How to choose the best sci fi books public domain

The founders first

The Time Machine by H. G. Wells is the book that introduced time travel, in an Enriched Classics edition. The listing describes the Time Traveller’s journey to 802,701 AD, the Eloi and the Morlocks, and the planet’s last days on a frozen red beach. The Gods of Mars and Warlord of Mars by Edgar Rice Burroughs are community-volunteer digital conversions, both published May 17, 2012 as Kindle editions, free on the web per the descriptions. The Skull by Philip K. Dick is a 37-page short at 102 KB. The Colors of Space by Marion Zimmer Bradley is a 237 KB Kindle edition.

Edition and length

The Time Machine is the only enriched print edition here; the rest are volunteer Kindle conversions. The Skull at 37 pages is the quickest read. Both Burroughs titles state 2012 Kindle publication and free availability on the web.

Setup Notes

• Volunteer conversions state you may find them free on the web; the Kindle editions include wireless delivery.
• Start with The Time Machine; it is the genre’s founding novella.
• Read The Gods of Mars before Warlord of Mars.
• The Skull suits a single sitting at 37 pages.

Frequently Asked Questions

Which is the founding work?

The Time Machine by H. G. Wells, the book that introduced time travel.

Which are Burroughs Mars books?

The Gods of Mars and Warlord of Mars, both 2012 Kindle editions.

Which is the shortest?

The Skull by Philip K. Dick, 37 pages stated.

Are these really free?

The Burroughs, Dick and Bradley listings state the books may be found free on the web; the Kindle editions add wireless delivery.

Still deciding? Our top pickThe Time Machine by Wells

Check price on Amazon

Related lists

See every Fantasy and Romantasy list and all Fiction lists. Also see our best sci fi books space opera. Also see our best sci fi books this century.

More lists: browse fantasy books, sci fi space opera and every fiction list.