Google is spending 12.5 billion US dollars (£7.6 billion) to buy Motorola Mobility.
But the big prize is not Motorola's line-up of mobile phones, tablet computers and cable set-top boxes - it is Motorola's more than 17,000 patents - a crucial weapon in an intellectual arms race with Apple, Microsoft and Oracle to gain more control over the increasingly lucrative market for smartphones, tablets and other mobile devices.
If approved by federal regulators, the deal could also trigger more multibillion-pound buyouts. Nokia, another phone manufacturer, and Research In Motion, which makes the BlackBerry, loom as prime targets.
The patents would help Google defend Android, its operating system for mobile devices, against a litany of lawsuits alleging that Google and its partners stole the innovations of other companies.
In addition to the existing trove of patents that attracted Google's interest, Motorola, which introduced its first mobile phone nearly 30 years ago, has 7,500 others awaiting approval.
Phone makers and software companies are engaged in all-out combat over patents for mobile devices. The tussle has been egged on by the US patent system, which makes it possible to patent any number of phone features.
Apple, for example, has patented the way an application expands to fill the screen when its icon is tapped. The maker of the iPhone sued Taiwan's HTC because it makes Android phones that employ a similar visual gimmick.
The iPhone's success triggered the patent showdown. Apple's handset revolutionised the way people interact with phones and led to copycat attempts, most of which relied on the free Android software Google introduced in 2008.
Android revolves around open-source coding that can be tweaked to suit the needs of different vendors. That flexibility and Android's growing popularity have fuelled the legal attacks. About 550,000 devices running the software are activated each day. Many upstart manufacturers, like HTC, had only small patent portfolios of their own, leaving them vulnerable to Apple and Microsoft.
Getting Motorola's patents would allow Google to offer legal cover for HTC and dozens of other device makers, including Samsung, that depend on Android.