For today’s engineers who were kids in the 80 s and the 90 s, robots and Japan have always been deeply intertwined. We nurtured our engineering dreams with the adventures of giant robots like Goldrake, Great Mazinger, and Voltes V.Footnote 1 These Japanese animated series offered us not only epic battles and heroic characters but also showcased technical feats and glimpses into the future. Somehow, reading the book The Science of Soft Robots, edited by Koichi Suzumori et al. and featuring contributions of several Japanese researchers, evokes similar impressions: an overview of the many facets of soft robots, a category of robots that are not yet widespread nor fully developed but which we are sure will play a key role in future robotics.

The book The Science of Soft Robots ambitiously explores the large field of soft robotics through a series of contributions spanning material science, biology, mechanics, and artificial intelligence. This interdisciplinary approach reflects the inherently broad and evolving nature of soft robotics, a field with indistinct boundaries. In the foreword, Cecilia Laschi notes that in Japanese soft robots are “sometimes referred to as iikagenb”, i.e., “vague” or “imprecise”, thus underscoring the field’s fluidity and the challenges in defining its scope. Later, in the introduction, a tentative definition confirms the very broad nature of soft robotics: “the concept of ‘soft’ robotics include not only a soft body in a physical sense but also soft movement and the ability to respond flexibly to any situation”. As readers delve deeper into the book, they may find that even this inclusive definition does not fully capture the diverse content presented, highlighting the field’s vastness and ongoing evolution.

In the preface, Koichi Suzumori et al. present their book as “a textbook or a technical book for students, engineers, and researchers interested in soft robotics”. However, this ambitious goal is only partially achieved. Due to the vast range of scientific disciplines covered, this text would likely prove too challenging for students. Additionally, the structure of the book itself does not facilitate reading and would not be the ideal support for organizing a course on soft robotics, regardless of the academic level. The lack of clear division into distinct sections, the inconsistent length and depth of chapters, and the occasional redundancy in content across chapters make it less suitable for structured learning. That said, we do acknowledge that The Science of Soft Robots may act as a reference resource for researchers interested in broadening their involvement in soft robotics; i.e., scientists who already deal with some aspects of this field but aim to know more about related fields. This researcher-oriented focus is evident in the inclusion of sections titled How to start X research, where X refers to topics, e.g., Anatomical in Chapter 3 and Soft Aerial Robots in Chapter 4. While these sections are generally brief and should not be intended as a comprehensive guide for beginners, when paired with the corresponding Challenges sections, they help researchers to establish links between their research activities and other soft robotics fields.

Following the introduction, the book is organized into three main parts: Design of Soft Robots, Soft Materials, and Autonomous Soft Robots. However, these three titles do not fully reflect the breadth of their respective contents. For instance, Part I extends beyond just design and Part III only partially addresses autonomy. The diverse range of topics covered poses challenges for the general reader, who might struggle to fully grasp the content without prior knowledge in specific fields. Familiarity with the methods, notations, and terminology of mechanics (primarily for Part I), chemistry (mainly for Part II), and other scientific fields is often required. Moreover, the way the content is presented to the reader is not uniform across the book, e.g., Chapter 4 gives a very clear introduction to robotic parts for manipulation and locomotion (including flying and swimming): such a presentation would in fact be suitable for preparing a course on the topic. A similar approach is followed in other key chapters, e.g., Basics of Polymer (Chapter 7), Biological Material (Chapter 8), and Soft Actuators (Chapter 10). Conversely, some chapters delve into highly specific topics, making it difficult to discern their connection to the broader themes of the book, e.g., Chapter 11 on Tissue-Interfaced Electronics.

We particularly enjoyed the chapters Soft Manipulation and Locomotion (Chapter 4, by Shinichi Hirai, Ryuma Niiyama, Taro Nakamura, Takuya Umedachi, Toshiyuki Nakata, and Hiroto Tanaka), Soft Actuators (Chapter 10, by Shingo Maeda, Yuhei Yamada, Hiroyuki Nabae, Kenjiro Tadakuma, Koichi Suzumori, Zebing Mao, Jun Shintake, Hideyuki Sawada, Yuya Morimoto, and Masahiro Shimizu), and Information Processing Using Soft Body Dynamics (Chapter 15, by Kohei Nakajima, Hideyuki Sawada, and Nozomi Akashi). Our preference is influenced by our personal familiarity with the topics: robotics, broadly speaking, for Chapters 4 and 10, and embodied intelligence for Chapter 15. We also felt that the writing and the organization of these chapters’ content was particularly good. For the typical readership of this journal, we believe that Chapter 15 stands out as the most rewarding. It is the only chapter to explicitly discuss evolutionary computation, highlighting its role as both an optimization technique and a tool for fostering adaptation, particularly in the context of embodied intelligence. Attentive readers will spot here and there many opportunities to plug in evolutionary algorithms as a methodology for solving design problems where the design space is, by nature, heterogeneous and the objective is, again by nature, imprecise. Indeed, these are the characteristics that define the essence of soft robotics.

All in all, The Science of Soft Robotics is an ambitious book that attempts to cover a young scientific field rooted in many diverse disciplines and aims at impacting many practical aspects of our future. While it is not exactly an easy read, nor an introductory textbook, The Science of Soft Robotics can serve as a reference resource for getting in touch with the many paths along which this science is developing.