It's been a busy week in mobile. Having already sold more than 4 million devices on pre-order, Apple's two new iPhones were available in stores worldwide today, prompting huge queues everywhere from Perth to London. In the same week, Google announced that it was seeking to expand the smartphone market in the developing world with the launch of the Android One project, which sees it collaborate with three Indian manufacturers to make high quality smartphones available for $100.

As a category of device the smartphone, and particularly the type of large screen smartphones dubbed 'phablets' by technology industry insiders, continues to grow at an astonishing pace. According to figures released earlier this month by analyst IDC, sales of phablets (defined as smartphones with screens between 5.5" and 7" in size) will outpace those of portable computers in 2015.

The growth of large-screen smartphones, such as Apple's new 4.7" and 5.5" devices also looks like it will prompt a further shift in mobile reading behaviour. For example, iOS 8, the latest generation of iPhone software, iOS 8, now bundles Apple's e-reading platform iBooks as default with new devices, meaning new uses will no longer need to visit the App Store before being able to read books on their phone. At the same time, Apple also gave iBooks a big promotional push with a campaign offering users free eBooks from bestselling authors such as David Nicholls and Robyn Hobbs.

We've blogged before about the power of default settings to affect the way consumers buy and consume content on electronic devices, but this year at Frankfurt Book Fair we'll be putting some all-important numbers on the true extend of mobile reading. Currently, the importance of the smartphone as a book delivery and consumption device is unquantified, as it lumps together reading activity that takes place on dedicated e-readers and tablets.

To change this we've commissioned the Mobile Reading Habits Survey, which will set out just how widespread mobile phone book reading is. This research will look at whether we are reading more books on our phones than we did a year ago. It will address how frequently and long do we spend reading on our handheld devices. And it will also cover the main barriers preventing us from reading more books on our mobiles.

The full findings of the Mobile Reading Habits Survey will be unveiled at the CONTEC Conference that precedes the opening of The Frankfurt Book Fair on Tuesday 7 October. Then on 8 October we'll be taking a closer look at the results on the Publishing Perspective Stage in Hall 8.0 as we bring together a panel of international publishers and digital experts to debate the rise of mobile reading. Covering everything from the latest technological innovations to what publishers are doing to encourage reading via mobile phones, it promises to be a fascinating insight on what could be a highly lucrative market.

THE GREAT DEBATE:  How much money is in mobile? Wednesday 8 October, 14:30-15:30 Hall 8.0, Publishing Perspectives Stage

Chair: Randy Petway, COO, advance Division, Ingenta

Andrew Weinstein, VP, Content Acquisition, Scribd

Carla Aerts, Global Digital Director, Cambridge University Press

James Luscombe, Marketing Technology Director, Pan Macmillan