This book is an introduction to computer architecture, hardware and software, presented in the context of the Intel x86 family. The x86 describes not only a line of microprocessor chips dating back to 1978, but also an instruction set architecture (ISA) that the chips implement. The chip families were built by Intel and other manufacturers, and execute the same instructions, but in different manners. The results are the same, arithmetically and logically, but may differ in their timing. Why the focus on the Intel x86? It was the basis of the IBM personal computer (PC) family and its spin-offs. It has transitioned from a 16 to a 32 to a 64-bit architecture, keeping compatibility for more than 30 years. It's an de-facto industry standard that has withstood the test of time. This book covers the Intel ISA-16 and ISA-32 architectures from the 8086/8088 to the Pentium, including the math coprocessors. A chart of ISA processors is included. The purpose of this book is to provide the basic background information for an understanding of the 80x86 family, the IBM Personal Computer (pc), and programming in assembly language as an introduction to the broader field of Computer Architecture. It will stress the pervasiveness of this pc-based technology in everyday things and events. It will provide an introduction to Software System Engineering and the Design for Debugging methodology. This book is a spin-off of a course in Computer Architecture/System Integration, taught in the graduate Engineering Science Program at Loyola College (now, Loyola University in Maryland). If we learn to program in the language c, for example, we can take our skills to any computer with a set of c-based tools. If we learn IA-32 assembly language, we have to relearn a language if we switch to a different architecture. So, why do we learn assembly language? Because it gives us insight into the underlying hardware, how it is organized, and how it operates. This book is dedicated to the graduate students in Engineering Science at Loyola College, Columbia Campus, who took the course EG-611, “System Integration I, the x86 Architecture and Assembly Language.” The course was given to hundreds of students over a span of 15 years by myself and others.