From the Publisher's Website:
Few of the many, many gamers who played through the familiar "green cover" version of the module by Tom Moldvay and Jean Wells ever realized that there had been an earlier, suppressed "orange cover" version by Jean Wells alone - the version now being posted here. For years the few copies that evaded the recall have fetched high prices at auction or in the Dealers' Room at Gen Con, typically sold shrink-wrapped so that the potential buyer could never compare it with the more readily available version. But it has never been accessible to the average gamer - until now.
Why then, of all the modules TSR put out in its glory days, did only this one see a recall? The answer lies in the art. Apparently when the adventure was distributed to the staff at the TSR offices, one of the senior executives flipped through his copy and hit the roof. Not only did he order the copies already sent out to stores recalled, but that night he or a member of his staff went through the employees' cubes and removed all the personal copies handed out earlier that day. Only the few copies belonging to employees who had taken them home that night escaped the confiscation. The rest ended up in a Lake Geneva, Wisc., landfill, along with all the copies TSR could reclaim from those already shipped out.
What was so objectionable? Take a look at the illustration on page 9, titled "The Illusion of the Decapus." A woman tied by her own hair, being menaced by nine men who threaten her with knives while tearing off bits of her clothing, is hardly wholesome, but rather mild by TSR's standards. After all, it pales in comparison with the cover of 1976's Eldritch Wizardry (a nude woman tied down to a sacrificial altar), or the various bits of actual female nudity in the hardcover Deities & Demigods rulebook (1980, just the year before), not to mention the various bare-breasted illos of harpies, mermaids, and even witches that had appeared in various D&D rulebooks over the year.
Perhaps it was a matter of context. After all, Deities & Demigods was part of the ADVANCED Dungeons & Dragons line, whereas D&D itself and the "B" line in particular were theoretically targeted at a somewhat younger audience. (In practice, most gamers made little distinction between the two, typically playing AD&D and adapting the D&D modules to those rules.)