This book is an excellent guide for Android programmers on how to tune their programs for the best speed of execution inside the Dalvik Virtual Machine (DVM). It helps readers write more efficient code, understand how DVM works and how virtual machines are designed and work in general, while emphasizing key concepts that any android Java programmer must understand. The book explains what happens to Java code from the time it is compiled to Java bytecode to the time that it is executed by the Dalvik virtual machine. It explains in detail the translation of Java programs to bytecode, then to Android specific dexcode and will enable programmers to have a better understanding of how their code executes inside the DVM.