Author James Shapiro has said it is “incredibly rewarding” to have written a book that “stands the test of time” after claiming the Baillie Gifford Prize For Non-Fiction’s winner of winners award.

Shapiro said the book, 1599: A Year In The Life Of William Shakespeare, had “defined my career” and the prize was his “crowning achievement”.

The £25,000 prize marked the 25th anniversary of the contest by selecting the best of 24 previous winners, spanning investigative journalism, biography and history.

Shapiro’s book was announced as the overall winner during a ceremony hosted at the National Museum of Scotland, Edinburgh, on Thursday evening.

Exploring a pivotal year in which Shakespeare produced some of his greatest works, it won the prize in 2006.

James Shapiro (The Baillie Gifford Prize for Non-Fiction/PA)

Shapiro told the PA news agency that he was “a little in shock and very happy” following the announcement, and that he was still “really fond” of the book.

“It’s incredibly rewarding to write a book that has stood the test of time,” he said.

“Having written a book that took me 15 years to research and write, and it’s now just about that many years since I won the prize – so in some respects, it has defined my career.”

He continued: “I wrote the book to find out how Shakespeare became Shakespeare, and now in a way the book has come out, James Shapiro has become James Shapiro – there’s a kind of symmetry in that.”

Shapiro added that he had never understood Shakespeare when he studied him in school, and had “sworn” never to take a university course on his works, instead learning about the playwright through watching his plays.

“I wrote the book for people like me who didn’t get Shakespeare, didn’t understand what was extraordinary about him,” he told PA.

“And I think having that perspective separated me from an academic approach, which defines what most professors do.

“I didn’t really care to do that, I cared to stick to people who had walked away from Shakespeare, if you will.

“Those who hadn’t probably would enjoy it, but those were not my main readers.”

A professor of English at Columbia University in New York where he teaches Shakespeare, Shapiro has written a number of book about the Bard, including 1606: The Year Of Lear and Shakespeare In A Divided America.

He has also served on the board of directors of The Royal Shakespeare Company, and advises on productions for the Public Theatre in New York and other companies.

“One of the most gratifying things for me is that actors and directors love the book,” he said.

“So in many ways, the book has been great for me – tonight is really a crowning achievement.”

Shapiro’s win comes in the same year as the 400th anniversary of the first printed edition of Shakespeare’s collection of plays, commonly referred to by modern scholars as the First Folio.

Author and academic Sarah Churchwell, who sat on the judging panel, said the anniversary had not been in their minds when they considered the shortlist.

She said: “We are not going to hold the fact it is a book about one of the greatest writers ever against it.

“We can’t say that we have an objection to a book about Shakespeare. The thing about this one is that it is a book about four masterpieces. For me, he reinvents those masterpieces.

“He makes me look at four major plays in totally different ways.

Shakespeare’s First Folio displayed at Guildhall Library – London
Shakespeare’s First Folio (City of London Corporation/PA)

“It is a good enough book if you can make me look at Hamlet differently.

“But if you can do Henry V and Julius Caesar and As You Like It and then Hamlet – if all of those come out reinvented and refreshed then that is an extraordinary achievement.

“We were thinking about it more in those terms than about Shakespeare’s anniversary.”

Asked what Shakespeare might think of his achievement, Shapiro told PA: “He would be happy that for centuries after he wrote his plays people are still staging them, still arguing about them, and in my case winning prizes – plucking out the heart of the mystery of Shakespeare.”

Other works that made the shortlist included Nothing To Envy: Real Lives In North Korea by Barbara Demick, Empire Of Pain: The Secret History Of The Sackler Dynasty by Patrick Radden Keefe, and Margaret Macmillan’s Paris 1919: Six Months That Changed The World.

Also featured were Wade Davis’s Into The Silence: The Great War, Mallory And The Conquest Of Everest and Craig Brown’s One Two Three Four: The Beatles In Time.