Fans of his fortnightly columns find his incisive, clear-eyed writing a tonic for bettering themselves and, by extension, their nation.
Han, a retired managing editor of The Straits Times, does this chiefly by asking hard questions that most Singaporeans often wonder about, but seldom voice publicly, lest they be thought disloyal for criticising the safe and secure life they have in the world's third richest country today.
But, as he said in his speech at the book's launch, his questions are meant to stoke discussion and debate. "Asking lots of questions is the first step to greater understanding of the challenges and what the options are. As a society, I don't think we ask enough questions. And because we don't, we often do not know or do not want to know where we've fallen short."
The hardest questions that form the undercurrents of his book, then, are these: "Do the old formulae for growing the economy still work? Can the country make a successful transition to more pluralistic politics? Will it continue to be a place where lives get better for every succeeding generation?"
Condensed in the form of a book, his 40 columns come across as a very strong dose of medicine, meant to spur Singaporeans on so they can stand tall as world- beaters.
One of the best, if bitter, spoonfuls is his essay from Jan 25 last year headlined "What dark secret is in the Singapore basement?", written at the start of Singapore's Jubilee Year celebrations.
In it, he takes a leaf from American science-fiction writer Ursula Le Guin's 1973 short story, The Ones Who Walk Away From Omelas.
Omelas is a fictitious paradisical city of contented people. The rub is, they can enjoy that happy state only as long as they keep a child imprisoned in a basement.
Those who cannot stand to think of how deprived and tortured that child is are the ones walking away from their supposedly heavenly home.
So, Han wonders, who might the child in Singapore's basement be? He then proffers three answers: The country's poorest earners, its foreign labourers and those who oppose its ruling party.
For too long, Singaporeans have tended to wave away such soul-searching with a dismissive "so cheem" (Hokkien for "deep").
Han's most valuable contribution has been to broach sensitive concerns in a friendly, conversational way that shows everyone why these are not so complicated to contemplate.
Here, for example, is his assessment of Singapore today: "The baby might already be 50 years old, but it had led such a sheltered life, it wasn't about to wander too far off the beaten track."
He is so good at drilling down to the root of any issue that newcomers to the Republic will be able to grasp readily its exceptionalism, as well as existentialist woes, such as having an electorate that is still rather conservative, slow to adjust to the skills of tomorrow and that chafes at being displaced by incoming foreigners.
He notes that, in prickling the Singaporean conscience for the better part of 27 years, he has some people worrying that the country may be "falling apart".
But as he writes: "Far better to be in this state than to be inert, unconcerned and afraid."
His is a kind of tough love, but love nonetheless, and his writings should be required reading for anyone who cares about Singapore.
FIVE QUESTIONS THIS BOOK ANSWERS