If you would like to take your first steps in mobile app development then a book worth a look is App Inventor for Android by Jason Tyler. It is aimed at people starting out in programming and those who want to know how to get the most out of Google's innovative app creation platform of the same name. The book takes you from the basics to some surprisingly advanced applications. For me it it is a significant book too as I worked on it as the Technical Editor, my first time in such a role.