The book introduces us to what a computer system is and how the computer system works.It further explains the constituent parts that makes up a complete computer system.Basic terminologies used in computing were defined and short cut key.The basic input/output port layout as well as the keyboard layout were discussed in details as well computer peripherals.Once the operating system is loaded and the computer system is turned on,the screen you see when the computer finish booting is called the desktop.The desktop icons, start menu and user interface used in microsoft xp operating system were explained as well as windows short cut key.I demonstrated how the internet explorer can be used as a web browser and the short cut key used in viewing and exploring web pages.Apart from the operating system which controls the overall activities of the computer system,we have application packages which can be loaded no the computer system.