Tonight he will be recrowned as "Emperor of all the world's second-hand book towns". There are more than 50 such bibliophiles' delights scattered across the world, from the United States to East Germany.
But Hay-on-Wye in Mid Wales is the undisputed fountainhead. On 1 April 1977 Mr Booth, now 60, declared the little town an independent kingdom and was duly enthroned with crown, sceptre and orb.
Today's ceremony will be performed by Stephen Davies, the first person to be born in Hay after its Unilateral Declaration of Independence. Mr Davies, a chef at a local hotel, is 21 tomorrow.
The weekend is being given over to celebrations that threaten to snarl up Hay's narrow streets. Jugglers, stilt walkers, buskers and mimers were yesterday beginning to arrive. The main procession will be headed by an "ambling band" rather than a "marching band", and for pounds 1.50 people can take part in an egg-and-spoon race.
A spit-roast suckling pig is on the menu at a pounds 15-a-head crowning dinner in Hay Castle, Mr Booth's impressive home overlooking a town largely brought back from the dead by his quixotic energy and shrewd business sense.
"Hay has more than 30 bookshops and millions of volumes. Books are too important to be left to academics and for every book in a library there are a hundred in bookshops," he said. He criticises universities, saying that manual labour is more important - "physical work has seen more books coming into Hay than in all of the Welsh universities."
Dismissive of official efforts to revive the rural economy, which is under threat in places other than mid-Wales, the soon-to-be emperor raps out slogans: "Abolish the Wales tourist board", and "God save us from the Development Board for Rural Wales [the quango charged with developing Mid-Wales]".
The King-Emperor is, needless to say, a genuine eccentric. Pointing to his matching white shoes and fingering his crown he said: "I bought these in California when I was opening a second-hand book shop there a few weeks ago." Hay is his home, but the world is his (second-hand-books) oyster.
As well as claiming the palm as the world's largest second-hand books town, Hay-on-Wye stages an annual literature festival that attracts thousands. Mr Booth once described it as a gathering of literary groupies. And when the literati flood into the town, tills ring in local restaurants and pubs and cheques are frantically written for signed copies of newly published works.
Set in marquees in a school's grounds, this year's festival runs from 22 until 31 May and will see the appearance of notables ranging from Lord Callaghan and Alan Clark MP to Stephen Fry and Anthony Clare.Reuse content