This is an introductory course on data structures concerning the various ways of organizing data so that the data can be accessed and manipulated efficiently by an application. A central concept is that of an abstract data type, which is a collection of data and a set of operations on the data. The course, therefore, focuses on the fundamental concepts, techniques, and tools for the design and implementation of abstract data types, following the teaching of object-oriented design and programming for computer problem-solving. We use the programming language C++ in this course.