Who is Jonh Percival Hackworth from The Diamond Age, or, Young Lady's Illustrated Primer and what is their importance?

John Percival Hackworth is a thirty-something software engineer working for Bespoke. He is married to Gwendolyn and has a daughter named Fiona. When the novel begins, his daughter Fiona is four years old. The Hackworths attend a party in honor of a local royalty's youth. During the festivities, he meets with Lord Finkle-McGraw, a powerful investor in the company that employs him. The Lord is impressed by his skills and culture. Hackworth is commissioned by Lord Finkle-McGraw to write and engineer a unique interactive book capable of helping to raise his granddaughter, Elizabeth.