In this tutorial, I will discuss three problems on networks data. (1) Measuring tie-strength: Given a set of people and a set of events attended by them, how should we measure connectedness or tie strength between each pair of persons? The underlying assumption is that attendance at mutual events produces an implicit social network between people. I will describe an axiomatic solution to this problem. (2) Network similarity: Given two networks (without known node-correspondences), how should we measure similarity between them? This problem occurs frequently in many real-world applications such as transfer learning, re-identification, and change detection. I will present a guide on how to select a network-similarity method. (3) Role discovery: Given a graph, how can we automatically discover roles (or functions) of nodes? Roles should compactly represent structural behaviors of nodes and generalize across various graphs.