The book covers basic computer concepts and historical development of computers. It outlines aspects of computer architecture and computer components. The need for data representation with emphasis on binary number system, used by computers is addressed.Data communication is key to modern communication and key concepts are discussed. Computer literacy emphasis competency in use of computer applications hence several common computer applications are illustrated. The intricacies of application development with comparative study of existing methodologies are outlined. A scenario is used to illustrate the need of methodologies in the development of an application. Application development entails term of reference, decision tables, pseudo code and Entity relationship diagrams. The book ideal is for undergraduate students.