The outgoing Microsoft boss says today's deal with Nokia is "win, win" for both firms - but what about their customers?
As it is announced that Microsoft is to buy Nokia's mobile phone arm we look back at their handsets through the years.
Nokia has unveiled its latest smartphone in what may be the company's last chance to reclaim a market lost to Apple, Samsung and Google.
Technology giant Nokia has launched a raft of new products including its first Windows tablet device and two new large-screen smartphones, or "phablets".
The new Lumia 2520 tablet, designed to "work anywhere", was unveiled at a news conference in Abu Dhabi.
Two new 6in (15cm) screen smartphones, or phablets, were unveiled - the Lumia 1520 and Lumia 1320 - offering easier access to apps and other new features.
"At Nokia we have found that tablet usage peaks between six and eight in the morning and between six and nine in the evening. During the rest of the day tablet usage drops quite dramatically," Nokia chief executive Stephen Elop said.
"We are looking to shift this trend - your tablet should be as mobile and as connected as you are."
Nokia investors have welcomed the Finnish firm's deal with Microsoft, sending shares in the company up more than 40% in Helsinki during trading today.
However, Microsoft shares fell almost 6% in early trading on Wall Street.
Technology giant Microsoft is to buy Nokia's mobile phone arm in a "bold step" in the smartphone market that will cost it about £4.6 billion
Outgoing Microsoft boss Steve Ballmer, who announced plans to retire last month, said: "It's a bold step into the future - a win-win for employees, shareholders and consumers of both companies."
Microsoft has agreed to buy "substantially all" of Nokia's mobile phone business at a cost of 5.4 billion euros (£4.6bn).
The deal, which is still subject to approval by Nokia shareholders and regulators, reportedly includes licences to the Finnish company's patents.
Nokia partnered in 2011 with Microsoft and uses Microsoft's Windows software to run its mobile phones.
Nokia has reported record sales of its flagship smartphone as it tries to reclaim lost ground to rivals Apple and Samsung. The firm sold 7.4 million Lumia devices in the second quarter of this year, an increase of 32%. It follows the launch of a string of new models.
However, Nokia also reported a fall in revenue. Net sales came to £4.9 billion, down 3% quarter on quarter. The firm admitted it has some way to go before it can pose a threat to Apple and Samsung,
Technology analysts have given mixed reviews to the new Nokia smartphone, the Lumia 925.
Andrew Hoyle from CNet praises the phone's metal design but questions whether the rest of the device will live up to the hype.
– Andrew Hoyle
With its new metal parts, the Nokia Lumia 925 is a sleek and attractive addition to the Windows Phone 8 range.Does it excite, though? No. It shares most of its key specs with the older Lumia 920 which doesn't really stack up well against the elite competition such as the HTC One and Samsung Galaxy S4.
We'll have to wait and see if the slight tweaks to the camera and the more sturdy build will make the 925 a serious smart phone contender.
Review website Pocket-lint said "We were hard on the Nokia Lumia 920 when it launched because of its size and weight. We preferred the slimmer and more managable Lumia 820. The Nokia Lumia 925 is the handset we wanted last November and we're glad it's here."
– Paul Thompson, mobile advertising firm BlisMedia
If you set this against the design qualities of Apple's iPhone and even the HTC One, it is slightly underwhelming and will not set it apart from its rivals, it doesn't even raise the bar any higher.
I would expect Nokia to continue to struggle to make an impact in the smartphone markets in the US and UK, especially as it has bet big on the windows operating system which has failed to get much traction with consumers despite the millions spent on marketing it.
Nokia has unveiled its latest smartphone, the Lumia 925. The device will sell for around € 469 (£397) before tax and will be available for sale as early as next month.
The company says the new design has its most advanced camera to date as well as a unique metal casing.
Jo Harlow, executive vice president of Nokia's smart devices said "We're advancing experiences on the Nokia Lumia portfolio, whether that means great new benefits for an existing Lumia owner or bringing new showcase devices like the Nokia Lumia 925".
"Its very important to us that we keep on innovating."
Nokia has unveiled a cheaper range of mobile phones at the Mobile World Congress in Barcelona.
The lowest priced is the 105 phone which will cost just £13.
It is expected to go on sale at the end of March and has a colour screen, FM radio, and a battery standby time of 35 days or 12.5 hours talk time.
The phone also has a speaking clock feature.
Nokia said: "We wanted to be able to offer a bit of fun, an extra surprise that provides a talking point for the owners.”