This is an introductory text, a successor volume to the authors' previous book Software System Development. A Gentle Introduction. It follows the software development process, from requirements capture to implementation, using an object-oriented approach. The book takes a practical viewpoint on developing software using object-oriented techniques. It provides the reader with a basic understanding of object-oriented concepts without getting lost in technical detail. It outlines standard object-oriented modelling techniques and illustrates them with a variety of examples and exercises, using Java as the language of implementation. A number of case studies are introduced and developed and the mapping from the design models to the implementation code is carefully traced. Software development is a skill that has to be learned by practice. Through their teaching, the authors have found that what students need is clear, practical guidelines, supported by a large number of graded examples and exercises. This was the approach taken in the authors'||''' previous book, which has proved to be popular and effective. Many current books on this topic are very theoretical and lack the practical dimension that is so important in the learning process. This book is designed as a first text for introductory undergraduate and conversion MSc O-O courses.