It has brought together old schoolfriends, jailbirds and families across the world, but now the internet is reuniting two works of Leonardo da Vinci that will provide scholars, engineers, artists, scientists and historians with an insight into the great thinker’s mind. In launching Turning the Pages 2.0 in association with Microsoft, the British Library (BL) has brought together his Codex Arundel and the Codex Leicester as online works of art, literature and theory.

Initially created as a kiosk application, Turning the Pages was developed, using Shockwave, for the internet. Version 2.0 focuses on being a web application from the outset.

Under chief executive Lynne Brindley’s guidance the BL has sailed a clever course between serving the public with the information it wants and generating revenue and creating beneficial relationships. Turning the Pages 2.0 is a good example of the strategy.

Two of Leonardo’s notebooks are now visible to internet users using Vista, the latest iteration of Microsoft’s Windows operating system. The Codex Arundel is one of the BL’s treasures, while the Codex Leicester belongs to Bill Gates , founder of Microsoft. Both the Arundel and Leicester are reunited as an online Turning the Pages experience, with the Codex Leicester only available via Vista in a neat bit of marketing-led philanthropy by Gates.

The two Codex publications offer the most significant insight into Leonardo’s scientific studies, including his observations of the moon. They provide 7,000 pages of his famed backwards-written notes and drawings. No other thinker in human history is so important to such a wide group of people, including engineers, historians, scientists and artists.

He composed what is now known as the Codex Arundel between 1508 and 1510 in his native Tuscany. The Codex Leicester was written over a much longer period between 1478 and 1517. This is probably the first time these two titles have been seen together since the death of Leonardo.

Turning the Pages has undergone a refit as an application. The site opens with a typically Vista view: the BL titles cascade backwards from the centre of the screen.

To enter the mind of Leonardo, you click on a book cover, and it moves to the front of the cascade, with the previous titles neatly taking their place at the back. A dialog box above the cover reveals the name of the title – and in the case of the Codex Leicester, its current owner, Bill Gates, too. One click on the View Book button in the dialog and you are staring down at a historic item of knowledge and literature in the most realistic virtual experience possible. Below the title a set of Turning the Pages functions lines up across the screen.

Regular users of Turning the Pages will notice some new toys in the box. There are tools for physically rotating the title and making notes on your findings. There are also useful essays with resizable text. You can move a title about on the desktop, which will be especially useful for viewing more than one text at a time.

The ability to rotate the text by 360 degrees may seem no more than a bit of fun until you get inside the work. Leonardo’s engineering work was of seminal importance and the ability to view his diagrams in a variety of angles helps understand how his devices could work. The M character key creates a mirror image of the text so you can read Leonardo’s reverse writing.

Turning a page is a simply incredible and realistic operation. There is a wonderful flex and shadow effect – you can almost hear the sound of paper turning. You can also navigate the titles by using a pair of traditional arrowed Next and Previous buttons below the text in the Tools menu, but this is slower than turning the pages.

Turning the Pages 2.0 has adopted Web 2.0 collaboration. You can make your own notes and share them with the Turning the Pages community or store them for private use. You can drag and drop notes about the desktop and they will reappear when you click on the Notes button again.

Viewing two texts at a time is also new and undoubtedly useful. From the Settings dialog, you tick a check box to allow multiple titles and then open another book from the Menu on the far left. You can then compare titles and swiftly swap from one to the other.

Turning the Pages 2.0 is a well-executed development of the application that retains the simplicity of the original, ensuring that academics, business users and amateur will all get the most from being able to view two rare titles online.