This is Kenner's 12" Large Size Boba Fett. He was released in 1979, at a time before his film debut in 1980's Empire Strikes Back. He had previously played a part in the animated segment of the Star Wars Holiday Special that had been shown on TV a year or two previously.
So, when this figure was released, we didn't have much of a clue who the character really was. There was quite a bit of hype around the character before the release of the Empire Strikes Back which included this figure and the now infamous "rocket firing" 3 3/4" Boba Fett that could be had by sending in enough Star Wars action figure proofs of purchase.
Kenner must have decided that they weren't putting enough play features into the figures of the Large Size figure line when they designed Boba Fett. For one, he was designed with quite a bit more articulation than any other figure of this line before. Boba Fett has lateral shoulder, elbow, wrist, and knee ankle articulation that most of the other large sized figures were missing. He was articulated more like a 12" Gijoe from this era rather than something more akin to Ken and Barbie like previous figures.
Boba features a see-through eye feature that was, seemingly, borrowed from Kenner's own Six Million Dollar Man figure. He also sports quite a few more accessories than was typical for this line. Another fun feature is a missile that can be removed from his backpack and hooked onto something like a grappling hook. A string attached to the "missile" allows Boba to hang or glide along the string.
This particular figure was our childhood Fett. It first belonged to my brother and then, eventually, became mine through a trade of some sort. My folks hated it when we did that. So, this guy is far from mint and has more than a few problems. One of his hands was torn off and then glued back on. His backpack is also missing one of the prongs for winding up the black cord that's attached to his missile. If you look closely, there's even glue on his face, presumably from "Operation Hand Reattachment."
This particular figure is complete, however, which is no small feat with this guy. He had quite a few accessories to lose over time. A complete Boba Fett should include his gun, belt, wookie scalps, shoulder cape, removable backpack, and a rubber tipped missile with attached string and loop.