Guy Cole is a veteran Silicon Valley contractor with engagements in many well-known companies such as Facebook, Cisco, Motorola, Cray Research, Hewlett-Packard, Wells Fargo Bank, Barclays Global Investments, DHL Express, and many smaller, less-famous companies. You can contact him via LinkedIn for your next project.

Krzysztof Fonał is passionate about computer science. He fell in love with this field when he was eleven. He strongly believes that technology doesn't matter; problem solving skills matters, as well as the passion to absorb knowledge. He currently works with Trapeze Group, which is a world leader in providing IT solutions. He plans to work with machine learning books and also on the Corona SDK.

Sergey Kosarevsky is a software engineer with experience in C++ and 3D graphics. He worked for mobile industry companies and was involved in mobile projects at SPB Software, Yandex, and Layar. He has more than 12 years of software development experience and more than 6 years of Android NDK experience. Sergey earned his PhD in the field of mechanical engineering from St.Petersburg Institute of Machine-Building in Saint-Petersburg, Russia. He is a coauthor of Android NDK Game Development Cookbook. In his spare time, Sergey maintains and develops an open source multiplatform gaming engine, Linderdaum Engine (http://www.linderdaum.com), and a multi-platform open source file manager, WCM Commander (http://wcm.linderdaum.com).

Raimon Ràfols has been developing for mobile devices since 2004. He has experience in developing on several technologies, specializing in UI, build systems, and client-server communications. He is currently working as a mobile software engineering manager at Imagination Technologies near London. In his spare time, he enjoys programming, photography, and giving talks at mobile conferences about Android performance optimization and Android custom views.