Student learning is the focus of teaching learning process but this process may be so complex that it can be considered as a ?black box? whose mechanisms are not fully understood. However, research into the nature of the learning process has thrown some light on what happens inside the ?black box?. This has enabled educational technologists to structure the input (teaching methods, aids, curriculum, etc), to systems of this type in such a way that optimal assimilation of the knowledge and skills takes place during the learning process, hence maximize the quality of the output. Teaching method is one of the most important inputs which can be structured in various ways and with different dimensions. Research conducted on children shows that they retain 20% of what they hear, 40% of what they see and hear and 75% of what they see and do. That is one of the key reasons why the latest technology has become essential to impart education. Computer Aided Instruction (CAI) is an integrated teaching method of such technology and education. In this book efforts have been made to develop a CAI package and analyze its impact on students achievement in educational research.