Today Krasis has released our new book about Apps for SharePoint and Office. This book was thinking to cover the new model of development for SharePoint Server 2013 and Microsoft Office 2013. The book is in Spanish and whom wants know, understand and learn about the new model to develop application for SharePoint and Office, must get this book :)
In the next days the book will be available in Amazon, but right now you can get it from here.
Here you can get the three first chapters, http://www.scribd.com/doc/165692912/Todo-Sobre-Aplicaciones-Para-SharePoint-Office-y-Office-365-Vvaa-Krasis-Press