Remember NetworkX? This is a book about NetworkX. NetworkX is a Python package for modeling, analyzing, and visualizing networks. It provides classes to represent several types of networks and implementations of many of the algorithms used in network science. NetworkX is relatively easy to install and use, and has much of the functionality built-in, so it is ideal for learning network science and performing analyses on small or medium sized networks. There is excellent documentation available on the project website at https://networkx.github.io/.
At the time of writing, NetworkX is in version 2.3. While many things are exactly the same between 1.x versions and 2.x, some basic functionality has changed, so documentation and books relating to older versions may no longer be accurate. This book assumes versions at or above 2.3, so all examples here should work with recent versions of NetworkX.
NetworkX is Free and Open Source Software (FOSS). That means that the source code is available to read, modify, and redistribute (under certain conditions). The code itself is available at https://github.com/networkx/networkx. In addition to the original authors and project maintainers, NetworkX has been written by a community of dozens of contributors. If you have an idea for a new feature or a way to improve the software, you can write it yourself and contribute it back to the community.