Interested in the pre-history of the coolest bounty hunter in the Star Wars universe? The Birth of Boba Fett chronicles some fascinating backstory, including what looks like a downright goofy first screen test for the costume, which was then painted white.
The article does show how well LucasFilm understands the reasons behind its characters' popularity:
By the time Empire rolled out of theaters in May, 1980, fans were well-aware that Fett would be making an appearance in the hotly-anticipated sequel. They may have been surprised, however, by the small amount of screen time given to a personality which had been trumped up by Lucasfilm for nearly two years. Though Fett's character suffered cutbacks in script rewrites, the ultimately short amount of time he spent on screen probably helped bolster the mythos which surrounds him. With so little revealed about the "galaxy's best bounty hunter," fans were allowed to fill in the details, making for a much more evocative and intriguing character. And with the filmed saga now complete, there seems to be no waning of interest in Boba Fett, whose character effectively embodies the danger and mystery found in the darker corners of the Star Wars universe.