Today's release of 'The Lost Symbol' is arguably the biggest event in the book publishing sector of the year.
Its sales are at least expected to equal those of the last Harry Potter book 'Harry Potter and the Deathly Hallows', which was bought by one in 10 UK households on the first day of its launch.
In the US the book's publisher Random House was forced to release copies to the media yesterday after the New York Times broke the embargo and posted a review of the book on Sunday.
The paper was swiftly followed by the Los Angeles Times, which published its own review.
In the UK both Waterstone's and Borders are holding a competition to become the first retailers to post their own reviews of the book.
Both received advance copies yesterday evening so book buyers could read through all 448 pages by this morning.
Waterstone's press officer Jon Howells, who updates on the retailer's Twitter page, finished at 5.10am.
Waterstones has 200 signed copies of the book for the first customers together with a Dan Brown goodie bag. It is also giving .
Borders has also brought in the world speed-reading champion Anne Jones to read the book at its Islington store and is also opening its stores early.
As with any major book launch many retailers are running massive price promotions. Asda has managed to get in the first blow and is selling the book for £5, £13.99 below its recommended £18.99 price.
Waterstones and Borders are selling the book for £9.49 and £13.49 respectively.
In the run-up to the book's launch, UK publisher Doubleday used social networking sites including Facebook to run brainteasers based around
As for the book itself the was generally positive. However it said the ending was "surprising for a strange reason -- It's unsurprising."