Searching for each title in dusty bookstores was like a quest, and actually finding an edition was like Howard Carter opening Tut's tomb.
I remember especially reading these Barsoom Ace editions when I was ill with the flu, about the age of 14. The writing blended with fever delirium, creating haunting visions of an exotic world where anything could happen. And I would refer to the artwork every other chapter just to remind myself how beautiful the visions were.
I was especially enamored of the Mars series more than Tarzan and the others, and the Ace editions had Krenkel masterminding those, as a loving tribute to his memories and visions passed down from J. Allen St. John.
I know this is La of Opar (what a wonderful name), but I have always associated it with how I pictured Dejah Thoris (another wonderfully delirious name).
Even the typography for the Ace editions added spice to the exotic flavor. I think that the title font is some form of Mephistopheles, a very fitting type design for Burroughs.