With the iPad 3 due to be announced in a matter of weeks, Adam Lashinsky has shed some light on Apple's extreme secrecy leading up to a product launch.

Lashinsky's book, Inside Apple, was released on January 25 and offers a never-before-seen insight into how Apple operates and how the company faces a future without its co-founder and former CEO, Steve Jobs.

"Apple employees know something big is afoot when the carpenters appear in their office buildings," Lashinsky writes. "New walls are quickly erected. Doors are added and new security protocols put into place."

Windows are frosted, some 'lockdown rooms' have no windows at all, select employees' electronic ID cards will no longer grant access to where they once did and operations are run strictly on a need to know basis.

If the ever growing mountain of rumours and speculation surrounding the iPad 3 is to be believed, then the device is ready for release, will be announced by Apple in February and will go on sale in either March or early April.

Expected to feature a faster processor and a super-high resolution Retina display, the iPad 3 will not be a huge update, it will be to the iPad 2 what the iPhone 4S was to the 4, an evolution not a revolution, but one which will no doubt see the world's media pay close attention and lead to fans queuing up for hours to buy one.

Lashinsky - who spoke to countless former Apple employees while writing the book - continues: "You quite likely have no idea what is going on, and it's not like you're going to ask. If it hasn't been disclosed to you, then it's literally none of your business.

"All you can surmise is that a new, highly secretive project is under way, and you are not in the know. End of."

The borderline absurdity of Apple's secrecy is not lost on the company however, as the retail store at its Cupertino headquarters sells t-shirts with the message "I visited the Apple campus. But that's all I'm allowed to say."

Aside from the occasional blurry photograph of what claims to be a component of the iPad 3, everyone but select Apple employees are completely in the dark about the next generation tablet.

Even employees joining the company are hired in secrecy and, according to Lashinsky, "many employees are hired into so-called dummy positions, roles that aren't explained in details until after they join the company."

Apple will release an updated iPad and it will probably appear soon but, despite the never-ending torrent of rumour and gossip from sources who might as well be called Mr X, all anyone knows for sure is that Apple can create a whirlwind of hype and speculation by saying absolutely nothing.