The book Urban soils. Principles and practice, edited (and mostly authored) by Rate (2022), presents abundant information about the properties and functioning of soils of urban areas. These soils are a topic of increasing interest with the intensification of urbanization in the past few decades, which need to be understood as a key component of urban ecosystems. The book covers topics, including the history of urban ecosystems, urban soil genesis and development, spatial variability, functions and contamination, physical and biological properties, their importance for human health, and remediation techniques. A large part of the book is devoted to detailed descriptions of general concepts in soil science, including soil components, functions, processes, and properties, which are undoubtedly essential to understanding urban soils. The book is well illustrated, with informative and useful schemas, plots, and figures summarizing results from scientific papers. The inclusion of questions and exercises at the end of each chapter makes the book a potential textbook for students in soil science.The book begins with a brief exposition of the history of urbanization and its impacts on soils. The second chapter presents urban soil genesis, using a structure that will be replicated in many other chapters: an introduction to the concept or problem for all soils followed by its application to urban soils. Although this chapter presents diverse examples of urban soils, including those found in landfills or archeological settings, a deeper examination of soil forming factors and processes specific to urban areas-as well as a description of typical horizons or a catalog of urban soil profileswould have been informative. Future editions might divide the second chapter into two sections, one devoted to formation processes and the other to urban soil morphology.The third chapter focuses on an important feature of urban soils: their much higher spatial variability than soils formed through natural processes, due to the human decisions that drive the distribution of urban soils. The chapter explains in much detail the statistics used to describe that variability in This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.