Very brief summary, covering philosophy and sort of a sales appeal... not changes since the first edition, etc. 

Write it dead last


But... here's some to work off

When Eric Berkman and I conceived and wrote the first edition of Designing Mobile Interfaces, the world of mobile was rather more complex than it is today. As much as everyone likes to complain about fragmentation, we had to contend with many more popular OSs, with ubiquitous featurephones, with an unclear niche for tablets, and the expectation that other devices like portable gaming, or stripped down eReaders would be a major force in mobile and portable computing.

Designing Mobile Interfaces was, in many ways, a manifesto against books like Tapworthy. While fine, wonderfully-done, even aspirational works, they also espoused a singular view of the world. And back then, that was either an iOS view, or a Web view. This has persisted, but been joined by a popular and often well-done Android-only world view, and the well-designed factions built around the also-ran Blackberry and Windows platforms. Designing Mobile Interfaces deliberately offered a generalized solution. Often, this exposed fundamental truths I didn't recognize before we started. Occasionally, it was a bit of a stretch. Sometimes, eliminating interesting but singular features or widgets as being too much of a particular platform.

In the very few years since then, the world has changed. Smartphones rule the market, eve if featurephones are still (so far) in more people's hands. Tablets have a home, and it's something other than a big phone. eReaders are just for reading. Game devices are also smartphones. There is much to be done on wearables, kiosks, home automation, and other critical interfaces, but these are -- like tablets -- something else and increasingly best pursued by experts in those fields.

And one more thing happened: The smartphone/tablet interfaces are starting to agree with each other on what it means to be a good GUI. As I write giant strategy screeds, and build style guides and pattern libraries, and assist developers for my clients, I have been finding that the variations between platforms are increasingly subtle, technical, and semantic. It is possible now to really make sense of principles of designing for every platform, using these common GUI elements, and better understandings of how people actually use their mobile devices.