JOHN CARTER, WARLORD OF MARS #20

Cover shows strong gloss and bright inks with sharp corners and only minor edge wear visible at the top right corner. There is slight waviness/line stress near the spine and a small amount of surface handling wear near the bottom staple area. No major creases, tears, or color breaks are visible in this photo; the book is in a protective sleeve which slightly obscures fine edge detail. Interior and back cover were not assessed.

John Carter, Warlord of Mars #20 continues Marvel's late-1970s adaptation of Edgar Rice Burroughs' Barsoom novels, with Chris Claremont scripting a chapter titled "Master Assassin of Mars" and Ernie Colon providing pencils and inks. Rudy Nebres supplies the cover art, working in the moody, painterly style he brought to several Marvel black-and-white and color adventure titles of the era. The series itself is a minor but recognizable entry in Marvel's Bronze Age sword-and-planet output, notable chiefly for pairing Claremont, then still building his reputation before his defining run on X-Men, with a licensed property that never achieved major sales traction.

Market data for this issue is thin, consistent with a low-demand back-issue title: census records show only 24 Universal graded copies out of 28 total, with no 9.8s certified and just a handful of copies at 9.6 and below. The 9.6 grade shows a modest but volatile average sale price, likely driven by a small number of transactions rather than sustained demand, and grades below 9.2 have essentially no recorded sales. This scarcity of data, rather than genuine collector competition, is the primary driver of whatever premium exists at the top of the grade scale.

This is a book for John Carter/Barsoom completists, Claremont bibliography collectors, and dealers filling out runs rather than a title driven by speculative or key-issue demand. Raw copies in low and mid grades trade cheaply and infrequently, largely through back-issue bins and bulk lots, while high-grade certified copies command outsized prices relative to the book's actual content value simply because so few have been submitted or preserved. Expect thin, sporadic sales activity across all grades rather than a liquid, actively tracked market.