The aim of this book is to design and implement data structures that can be used in applications. The approach we use is very practical. Real-life applications are explained and developed gradually from scratch with an emphasis on the different types of data structures. The book comes full of figures and examples that help the reader to understand the concepts of data structures. It contains many multiple-choice exercises and programming exercises that are useful to help master the topics. It is the first data structures book that is written in both English and Arabic languages, side-by-side. It is the first data structures book that presents examples in three programming languages, C++, C#, and Java. It is a unique, multi-language book by all meanings. In conclusion:1. It is Practical, you learn from real-life examples.2. It is written in English and Arabic, side-by-side.3. It uses three well-known, and well-used computer programming languages, C++, C#, and Java, also side-by-side.4. The lines of code are explained in simple, easy to understand.5. Each chapter ends with multiple-choice exercises and programming exercises. 6. It covers the main subjects of data structures, such as classes and objects, arrays and arrays of objects, linked lists, circular doubly linked lists, stacks, queues, trees, and graphs.