JOHN CARTER, WARLORD OF MARS #21

Cover shows strong gloss and vibrant color with sharp corners and no visible creases or tears. There is minor edge wear at the top right corner and slight whitening along the top edge, and the book is in a protective sleeve which limits full assessment of surface sheen. Spine appears tight with no visible stress lines or ticks in this view. Interior and back cover were not assessed.

John Carter, Warlord of Mars #21 (Marvel, February 1979) continues the publisher's Bronze Age adaptation of Edgar Rice Burroughs's Barsoom novels, a series that translated the planetary romance genre into Marvel's house style during a period of broad licensed-property experimentation. The issue falls within the run's later stretch, featuring the series' recurring cast of John Carter, Dejah Thoris, and Tars Tarkas, with cover art credited to Rudy Nebres, an artist closely associated with the title's visual identity in its second half. The book carries no first appearance, origin story, or other landmark creative event, and its place in comics history is as a representative chapter of a niche adaptation series rather than as a standalone touchstone.

Market data reflects a book with limited but steady collector interest concentrated at the high end of the grading scale. Sales at 9.0 through 9.6 sit in a narrow band near $28, suggesting little grade-sensitivity in the low-to-mid tiers where demand is driven mainly by series completists rather than speculative buyers. The 9.8 tier shows a meaningfully wider gap, with recorded sales and averages converging near $150, indicating that pristine, top-census copies command a real premium even though overall trading volume for the issue remains modest across all grades.

This is a book for John Carter/Burroughs completists and Bronze Age Marvel run-builders rather than crossover or key-issue investors. Lower and mid-grade raw copies trade as inexpensive filler within longer runs, with value driven almost entirely by convenience of acquisition rather than scarcity. The meaningful value tier is the CGC 9.8 slab, where a small surviving population and consistent sales support a durable premium; collectors seeking this title in top condition should expect to pay a multiple of raw-copy pricing, while lower grades remain accessible entry points for readers assembling the full Warlord of Mars run.