Dan Brown to release new Robert Langdon book Inferno in May

Dan Brown's novels have sold millions of copies worldwide

Dan Brown, the bestselling author of The Da Vinci Code, is to release a new book in May.

Titled Inferno, it will be the fourth novel in the crime series following Harvard symbologist Robert Langdon.

Brown said he was influenced by Italian poet Dante's classic work, Inferno, while researching in Florence.

Set in Italy, the book will see Langdon drawn into "a harrowing world centred on one of history's most enduring and mysterious literary masterpieces".

"Although I studied Dante's Inferno as a student, it wasn't until recently that I came to appreciate the enduring influence of Dante's work on the modern world," Brown said.

"With this new novel, I am excited to take readers on a journey deep into this mysterious realm…a landscape of codes, symbols, and more than a few secret passageways."

The book's title was revealed via posts on social media sites including Twitter and Facebook.

Every time fans mentioned the novel, a piece of a mosaic was unlocked which eventually revealed the name.

The image appears to show The Basilica of Saint Mary of the Flower - otherwise better known as the Duomo - in Florence.

It is not the first time puzzles have featured as part of the marketing campaign for Brown's novels.

A number of codes, puzzles and teasers were released to coincide with the launch of his last novel, The Lost Symbol.

Brown's Langdon novels have sold millions of copies worldwide.

The Da Vinci Code is the best selling novel in the UK, in terms of print sales, and has been translated into 51 languages.

Both The Da Vinci Code and Angels and Demons have become Hollywood movies, starring Tom Hanks in the title role.

A movie version of The Lost Symbol is still in development.