Most of the current applications of electronics require non-volatile memories, which can keep stored information when the power supply is switched off. Flash memories (in which a single cell can be electrically programmed and a large number of cells are usually electrically erased at the same time) are the most versatile non-volatile memories. They are widely used to store the basic input-output system (BIOS) of personal computers, the software and personal data of cellular phones, identification codes in smart cards and many other applications. Flash memories allow software updates, change of passwords and codes, and reconfiguration of the system in the field. They can be designed and optimized to create large-size memories which can successfully substitute hard disks for specific applications, having lower power consumption and weight, shorter access times, and far better robustness. This book is devoted entirely to flash memories and has been designed to provide comprehensive information on basic memory cell structures, device physics and technology, simulation circuit architecture, system issues, testing and reliability. It also provides data on advanced subjects related to multi-level storage cells, embedded memories and system applications of flash memories.