The Surface Book, which Microsoft calls the ultimate laptop, is already sold out. It has been available for pre-order at the Microsoft Store, but all device options are presently no longer available. 

The Surface Book is, technically, the first laptop built by Microsoft. The company touts the device as the future of mobile computing, citing its high performance as a laptop and its supposed unprecedented versatility as a tablet.

It is also distinguished from the Surface Pro product line because it is not tablet-centric. Rather, it is being marketed as a laptop-hybrid, according to Tech Crunch. Eager buyers wiped out the priciest models first, and the cheaper ones followed suit. 

The pre-order performance of the Surface Book in the Microsoft Store does not necessarily indicate that it is selling better than expected, according to Mashable. One of the reasons could be that Microsoft has reserved a smaller pre-order stock.

There is also the case of Microsoft Band device, which initially sold like crazy, but performed dismally in the long-run, noted PC World. As of this writing, the laptop is still available for pre-order at Amazon, Bestbuy and Fry's Electronics - although the more expensive variants are also selling out fast.

If the Surface Book does indeed continue selling like hotcakes, it would be a little surprising. This is because the laptop's price ranges from $1,499 to $2,699, making it one of the most expensive on the market.

For those who can wait, the Surface Book officially rolls out in retail and online stores on Oct. 26.