This book is the first in a series of three books that teach the fundamentals of embedded systems as applied to the ARM(r) Cortex(tm)-M3. The first book Embedded Systems: Introduction to the ARM Cortex-M3 is an introduction to computers and interfacing focusing on assembly language and C programming. The second book Embedded Systems: Real-Time Interfacing to the ARM Cortex-M3 focuses on hardware/software interfacing and the design of embedded systems. The third volume focuses on real-time operating systems, digital signal processing, and digital control systems. The third volume is primarily written for senior undergraduate or first-year graduate electrical and computer engineering students. The third volume could also be used for professionals wishing to design or deploy a real-time operating system onto an ARM platform. This first book is an introductory book that could be used at the college level with little or no prerequisites. An embedded system is a system that performs a specific task and has a computer embedded inside. A system is comprised of components and interfaces connected together for a common purpose. This book is an introduction to embedded systems. Specific topics include microcontrollers, fixed-point numbers, the design of software in assembly language and C, elementary data structures, programming input/output including interrupts, analog to digital conversion, digital to analog conversion.This book employs many approaches to learning. It will not include an exhaustive recapitulation of the information in data sheets. First, it begins with basic fundamentals, which allows the reader to solve new problems with new technology. Second, the book presents many detailed design examples. These examples illustrate the process of design. There are multiple structural components that assist learning. Checkpoints, with answers in the back, are short easy to answer questions providing immediate feedback while reading. Simple homework, with answers to the odd questions on the web, provides more detailed learning opportunities. The book includes an index and a glossary so that information can be searched. The most important learning experiences in a class like this are of course the laboratories. Each chapter has suggested lab assignments. More detailed lab descriptions are available on the web. Specifically for this volume, look at the lab assignments for EE319K. For Volume 2 refer to the EE445L labs, and for Volume 3, look at the lab assignments for EE345M/EE380L.6.There is a web site accompanying this book http://users.ece.utexas.edu/~valvano/arm. Posted here are Keil(tm) uVision(r) and Texas Instruments Code Composer Studio(tm) projects for each of the example programs in the book. You will also find data sheets and Excel spreadsheets relevant to the material in this book. The book will cover embedded systems for the ARM(r) Cortex(tm)-M3 with specific details on the LM3S811, LM3S1968, and LM3S8962. Most of the topics can be run on the simple LM3S811. In this book the term LM3Sxxx family will refer to any of the Texas Instruments Stellaris(r) ARM(r) Cortex(tm)-M3-based microcontrollers. Although the solutions are specific for the LM3Sxxx family, it will be possible to use this book for other ARM derivatives.