Ying-Dar Lin, Ren-Hung Hwang, and Fred Baker's "Computer Networks: An Open Source Approach" is the first text to implement an open source approach, discussing the network layers, their applications, and the implementation issues. The book features 56 open-source code examples to narrow the gap between domain knowledge and hands-on skills. Students learn by doing and are aided by the book's extensive pedagogy. Lin/Hwang/Baker is designed for the first course in computer networks for computer science undergraduates or first year graduate students.