It is an unequivocal sign of achievement, a red-bound record of success displayed in every library in the country. It is also a chance for a head to tell the world that she keeps donkeys.
Pam Barber, head of Lancaster girls' grammar, is among 15 education professionals to be added to this year's edition of Who's Who.
Her entry includes her date of birth, qualifications and career history.
But it takes a more idiosyncratic turn in the final section, in which entrants can list hobbies.
Along with foreign travel and horse-riding, Ms Barber lists donkey-keeping.
"Yes, it's quite peculiar," the 57-year-old said. "But so is being in Who's Who."
Each year, a panel consults with education experts to select heads and officials for inclusion.
Among those selected this year are Sir Ken Robinson, author of All Our Futures, a 1999 report into creativity in schools. Jonathan Shephard, the new general secretary of the Independent Schools Council, is also included.
Nine heads are among the new entries. Those who run renowned institutions are automatically invited, as are new knights and dames. Heads whose schools have done well in the league tables over several years are also considered, along with those who have sat on government committees.
Ms Barber said: "Often, because you're running a selective school people think you have an easy job.
"But I've been doing this for 18 years and I've survived. Maybe that's what this recognises."
Sir Dexter Hutt, head of Ninestiles comprehensive, in Birmingham, is among the Who's Who debutantes, but he is underwhelmed by his new status.
"You see films about medieval knights and King Arthur's Round Table," he said. "You don't see films about Who's Who. A knighthood is a far greater honour. I won't be bringing the book out for dinner-party guests. I'm not sure they'd approve."
Among those heads whose entry follows recognition in the Queen's honours is Dame Jean Else, head of Whalley Range grammar, in Manchester.
She was suspended in December last year after an Audit Commission investigation, but her entry has nonetheless appeared.
Dame Jean was unavailable for comment, and Who's Who will not discuss specific entries. But a spokeswoman said an invitation would never be rescinded.
"Once someone is in, they stay in until they die," she said.