Nearly all cells can move, often directionally. Without migration, embryos would not take shape, the nervous system would not wire, wounds would not close, and immune defenses would falter. Yet migration also underlies inflammation and cancer metastasis, a reminder that it both sustains and undermines life. This volume, with contributions from an international team of experts, shows that our knowledge of how cells migrate is rapidly advancing and the field is very exciting one to work in. Each of the four sections of the book has a specific focus:Single-cell migration, including key features of directed movement - cell polarity and memory, excitability and inhibition of signaling, cytoskeletal force generation, adhesion and traction - and the quantitative tools needed to analyze and model them. The coordination of cells in groups, how tissues remodel and respond, and the expression of these processes in development The technological advances and experimental tools that have advanced our understanding The multiple computational and mathematical models that have provided insights and how machine learning techniques are poised to accelerate discovery There are recurring themes throughout -- the interplay of biophysics and molecular signaling, the influence of microenvironment mechanics and signals, the value of standardized assays and quantitative imaging, and the power of computational modeling. Cell Migration offers both a coherent map of the field and signposts for future investigation.