05/31/2011 03:09 pm ET Updated Jul 31, 2011

Georgina Bloomberg's Young-Adult Novel 'Circuit' Sheds Light On Mayor Bloomberg, Family

Those who inhabit the rarefied world of Michael R. Bloomberg, with all its perks and payouts, have long adhered to a strict code of silence about his personal life: jaunts to Bermuda are cloaked in secrecy, tax returns are heavily redacted and even his golf handicap is off limits.

But perhaps no single sphere of Mr. Bloomberg's life has been as thoroughly walled off as his family, a realm that still seems, even after a decade in public life, unknowable.