Franklin's greatest invention was his own public persona

Isaacson's organizing thesis is that Franklin spent his adult life deliberately constructing, publicizing, and revising a public identity: the frugal, witty, self-taught tradesman who rose through diligence rather than birth. This wasn't incidental to his other achievements; Isaacson treats it as itself a calculated act of invention, on par with anything Franklin built in a laboratory.

From his early published essays under invented personas to the carefully managed image of the fur-capped frontier sage he presented in Paris, Franklin understood that reputation was a tool to be built methodically, not a byproduct to be left to chance. He wrote and rewrote his own autobiography with later readers explicitly in mind, shaping how history would remember him even as he lived it.

Isaacson doesn't present this as cynical manipulation so much as strategic self-awareness: Franklin grasped, earlier and more completely than his peers, that in a new society without inherited titles, a reputation for usefulness and trustworthiness was the only currency that mattered.

Takeaway: reputation isn't a passive reflection of character; Franklin treated it as an ongoing project worth deliberate design.