# Is "The Sword of Rhiannon (Sea-Kings of Mars)" by Leigh Brackett a First Edition?

> **Quick answer.** A first edition of The Sword of Rhiannon (Sea-Kings of Mars) by Leigh Brackett (Ace Books, 1953) is identified by: First book edition is the paperback original Ace Double D-36 (1953), bound dos-a-dos with 'Conan the Conqueror' in the Ace double. The magazine ('Sea-Kings of Mars,' 1949) is the first text appearance; the Ace Double D-36 is the first book edition (a paperback original).

**Checklist — a true first has these:**
- First book edition is the paperback original Ace Double D-36
- , bound dos-a-dos with 'Conan the Conqueror' in the Ace double
- The text first appeared as 'Sea-Kings of Mars' in Thrilling Wonder Stories
- Ace double number D-36 and dos-a-dos format identify the first book edition
- Publisher imprint reads Ace Books
- Not a book-club edition (see below)

| | |
|---|---|
| Author | Leigh Brackett |
| Publisher | Ace Books |
| Year | 1953 |
| True first | — |
| Format | Hardcover (trade) |
| Key point | First book edition is the paperback original Ace Double D-36 |
| Book-club edition exists? | No |

## Points of issue
First book edition is the paperback original Ace Double D-36 (1953), bound dos-a-dos with 'Conan the Conqueror' in the Ace double. The text first appeared as 'Sea-Kings of Mars' in Thrilling Wonder Stories (1949). Ace double number D-36 and dos-a-dos format identify the first book edition.

## Is this the true first?
The magazine ('Sea-Kings of Mars,' 1949) is the first text appearance; the Ace Double D-36 is the first book edition (a paperback original). Later standalone Ace reprints are first-thus.

## Telling it from reprints & book-club editions
No book-club edition. Distinguish the dos-a-dos D-36 double from later single-volume Ace reprints.

## Source
New Mexico Literacy Project — Is *The Sword of Rhiannon (Sea-Kings of Mars)* by Leigh Brackett a first edition? https://newmexicoliteracyproject.org/first-edition/the-sword-of-rhiannon-sea-kings-of-mars
CC BY 4.0. Part of the Canonical First-Edition Points of Issue dataset (https://newmexicoliteracyproject.org/api/first-edition-titles.json). Last reviewed 2026-07-04.