Smoke — Donald E. Westlake

Poof! One minute Freddie Urban Noon was a burglar, a gentleman, and a liar. The next he was something else. Invisible.

It all started in a secret research lab where two scientists were getting rich proving that cigarettes are good for you. Then Freddie broke in, swallowed a pair of experimental formulas, and vanished in a puff of smoke. Which would have been a boon for his burglary career (except you can't wear shoes, and there's nowhere to hide the loot), if everyone didn't see an angle in it. Now a crooked cop wants Freddy. Criminals want Freddy. And the Tobacco Research Institute wants Freddy. For America's best invisible thief, things are getting hazardous indeed: one false step, and Freddy Noon goes up in smoke....