Food shortage across the world demands an optimal use of natural resources. This book aims to optimize food production methods by combining them with advanced underground wireless technology. There are many books available on wireless sensor networks and wireless underground communications. However, what makes this book stand out is that it is the first book that specifically targets the agricultural sector in terms of both underground communications and sensing perspectives. The target readership of the book includes graduate students, researchers, industrial practitioners and faculty members who are either beginning or already working in the area of Internet of Underground Things (IoUT), wireless underground sensor networks, sensor systems and precision agriculture. The authors give an empirical account of how wireless sensors and communication systems would work if implemented in the agriculture sector. To the best of the reviewer's knowledge, there is no book that provides such an advanced tutorial content on underground sensing and communications for the agriculture sector.

The book is organized into four parts and a total of 13 Chapters. Part I provides an overview of the physical layer in wireless underground communication (WUC). Part II covers the basic components of WUC including antennas and wireless channels, and the challenges faced in deploying those components in harsh underground environments. Part III focusses on sensing systems and provides a detailed account of various sensing systems already deployed in agricultural and other underground applications. Finally, Part IV presents a complete IoUT ecosystem with sensing and communication systems. A chapter-wise account of the book is given below.

Part I introduces the field to the beginners and consists of three chapters. Chapter 1 starts with an introduction to the WUC and how it is different from the traditional over-the-air communications. Chapter 2 elaborates the effect of underground communication medium, i.e. soil, on electromagnetic waves in terms of return loss, bandwidth, path loss and frequency. Chapter 3 provides a discussion on the various channel and propagation models in underground communication, including the two-ray underground reflection model, underground channel impulse response model, and underground statistical and attenuation prediction model.

Part II consists of four chapters. Chapter 4 covers various modulation schemes available for underground communication. It analyzes the performance of multi-carrier modulation, soil and spatial-based modulation, cross-modulation and medium access modulation. It also addresses the effect of interference and connectivity in underground communication. Chapter 5 discusses different metrics that can be used to evaluate the performance of underground communication, including channel capacity for single and multiple users, channel bandwidth and bit error rate. Chapter 6 provides the design of special antennas used for underground communication. It presents the effect of operational and resonant frequency on underground communication along with the discussion on path loss of different types on antennas, such as planar and dipole. Chapter 7 provides a detailed account of the underground phased arrays and beamforming applications.

Part III is focused on sensing systems and technologies and consists of two chapters. Chapter 8 provides a detailed review on different types of sensing systems and their challenges. It also details a sensor calibration method along with a comprehensive sensor scoring system to select a sensor as per an application's requirement. Chapter 9 discusses the effects of soil properties on sensing systems, such as the effect of soil moisture, path loss and power delay profiles. The chapter also presents various models to map those effects.

Part IV presents the IoUT ecosystem and consists of four chapters. Chapter 10 covers the architectures, components, applications and the existing testbeds for the IoUT ecosystem. Chapter 11 presents the current state of implementation of decision agriculture in different parts of the world. Various agricultural decision support systems are also discussed along with their implementation challenges. Finally, the book is concluded with two applications of IoUT in agriculture, i.e., irrigation management and variable rate application, in Chapters 12 and 13, respectively. Chapter 12 presents sensor-guided irrigation systems for smart agriculture. Chapter 13 covers variable rate application systems and their hardware and software architectures.

In a nutshell, the book is very well-organized with rich information on how to implement communication and sensor systems in harsh underground environments. The book is well-suited for graduate courses on wireless communication and wireless underground sensor networks. The book is self-contained starting from the beginner level details and gradually progressing to advanced concepts and finally summarizing the complete information by presenting the applications of underground sensing and communication systems. Each chapter of the book concludes with references for the readers to dig deep into the research and development of any specific area of their choice. Another important feature of the book is its availability in hardcover and electronically at affordable prices for librarians, researcher and even for graduate students. A few improvements can be made in the second edition by providing more information on sensing systems in Part III.