This document discusses cross-platform mobile development. It defines cross-platform development as developing applications that can run on multiple platforms simultaneously. The document then explores different cross-platform approaches like web apps, hybrid apps, interpreted apps, cross-compiled apps, and generated apps. It provides details on how each approach works and when they are involved in the development process. The document also compares the different approaches based on factors like native access, performance, cost, and tools. It concludes that cross-platform options are not fully mature but can be good choices for prototypes, existing web apps, or as a shortcut to the market.