Boba Fett was the 21st toy photo released in the Star Wars line.
Copyright on cardback reads 1978, but it was released in 1979. The artwork here is sometimes called "fireball."
One version included text on the bottom right, which is the normal release. Another version did not include text.
One AFA 85 21-back sold for $8,260 in March 2019 (Hakes).
The text version is as follows:
* A fearsome interplanetary bounty hunter.
* A threat to the Rebel Alliance, especially Han Solo!
* A New Character in "Star Wars, The Empire Strikes Back."
* 21A: For the first time, Boba Fett appears among the figure photos. As on SW20A, the prototype versions of the Patrol Dewback and Droid Factory are shown.
* 21B: Same as SW21A, only the prototype Patrol Dewback and Droid Factory have been replaced with their production counterparts.
* 21C: Same as SW21A or SW21B, only a sticker appears over the bottom 2/3 of the card which shows an ad for the "SECRET STAR WARS ACTION FIGURE" (Bossk).
* 21D: Same as SW21C, only a sticker appears over the bottom 2/3 of the card which shows an ad for the "SECRET STAR WARS ACTION FIGURE".