Home security systems with facial recognition, laundry machines that send text messages, telephones that pay for groceries. All this is made possible by the incredible work of software platforms, those invisible engines that power industries as far reaching as PCs, PDAs and video games, mobile phones, digital media and web-based software such as Google and Ebay.But technology is only half of what makes these engines cool—the harder part is figuring out how to actually turn “cool” into cash. How many cutting edge ideas fall away after failing to figure out how to make money? What all software platforms have in common is the need to interest and engage multiple customer groups at the same time. Developers only want to write applications for platforms that have lots of customers, and customers won’t buy software platform based products unless there are enough interesting applications. Invisible Engines tell the story of the most vibrant software engines and how they transcended “cool” to become profitable fixtures in today’s economy.