Here is a book for those among us who are at the dawn of the 21st century. It invites us on a journey to the heart of this new digital world, whose “shores” were discovered a little more than half a century ago. This new world is revolutionizing our present lives and is going to have an even greater impact on future generations.

Computer science is a young science that has progressed exponentially but already has its history. This book does not pretend to have an exhaustive body of knowledge about computer science; there are a plethora of excellent books on this topic! Rather, it conveys a personal vision of this vast field through a professional life that is in constant “synergy” with research and innovation in computer science. As a privileged witness of this period, Jean-Loïc Delhaye invites us to journey through the progress that marked this “revolutionary” era.

In contrast to other sciences, such as mathematics, computer science (digital science) was created in close connection with computer technology. This is what contributes to its originality, and also its difficulty, as the development of technology is so fast. With the benefit of hindsight, Jean-Loïc Delhaye introduces us to the essential components of a digital environment, from computers to networks, from operating systems to the most advanced and popular applications.

The first chapter focuses on the basic “component”, the computer. It takes us back in time, from Pascal’s arithmetic machine, to the well-known calculator, to classic electronic computers (von Neumann architecture), and then up to supercomputers (which were the domain of Jean-Loïc Delhaye’s predilection for several years). This chapter is a remarkable concentration of several decades of progress leading up to the processors and computers that now surround us in our daily lives.

One of the key developments in recent years has been the emergence of computer networks. Indeed, what could be more natural than to allow different computers to communicate with each other and cooperate in order to carry out increasingly complex tasks? Chapter 2 gives us a complete overview of the characteristics of the various networks and inevitably leads to discussions on one of the great inventions of the end of the 20th century: the Internet. In just a few pages, Jean-Loïc Delhaye succeeds in allowing us to discover this mysterious world of computer networks, a world that he came into close contact with during his career.

These first two chapters provide the hardware basis on which it is possible to “develop” systems and all kinds of applications. In order to solve a problem, it is necessary, starting from a precise description of the problem, to design a proper solution. This solution, called an algorithm, takes the form of a “sequence” of commands that “transform” data into a “result”. This sequence of commands is, a priori, independent of any machine. For an execution on a given machine, in a given environment, this algorithm will be translated into software (or program) that is expressed in a computer language. Chapter 3 is entirely devoted to software and constitutes an excellent overview, even going as far as questioning legal protection (a subject on which Jean-Loïc Delhaye acquired a rare skill during his years at INRIA).

Chapter 4 deals with another crucial topic in computer science, namely that of data, its representation and storage. Unlike algorithms, which have been (and still are) a subject of both theoretical and practical study, data has often been neglected. The most common structures were tables, files, records and classical values such as integers, reals and Booleans. Then it was realized that data, although characterized by its values, was also especially characterized by the operations that could be applied to it, hence the numerous studies on data abstraction that gave rise to concepts such as classes and objects, common nowadays in programming languages. In this chapter, Jean-Loïc Delhaye gives a complete overview of data, including databases and “Big Data”. Big Data is at the root of a major development in current computer science: by exploiting it “intelligently” and highlighting certain global properties used for various purposes; this subject will be discussed in Chapter 7.

Several subjects are at the heart of the concerns of research and development organizations today; it is a question of creating environments that will enable the development of tomorrow’s applications. Jean-Loïc Delhaye has highlighted four essential “technologies” that concentrate much work around the world: 1) embedded systems, 2) artificial intelligence, 3) the Internet of tomorrow, 4) images and vision. For each of them, he proposes an overview of the issues and provides a panorama of the most current questions.

As the key technologies are developed, they constitute the “building blocks” from which large-scale applications can be implemented. In Chapter 6, Jean-Loïc Delhaye takes us on a rapid journey to the heart of tomorrow’s world: robotics, virtual reality, health, mobility, energy, the factory of the future, etc. It is not only fascinating, but also speculative.

Chapter 7 addresses the difficult question of the societal impact of these advances. The major questions concern security when using these technologies, respect for privacy, the potential influence that these new systems (known as artificial intelligence systems) can have on citizens’ freedom, and even the questioning of democracy as we know it. It also addresses the central issue, often forgotten by our elites and technologists, of the digital divide. We have to only look around us or travel a little to realize the extent of the problem. Jean-Loïc Delhaye approaches these subjects in a simple and factual way to provoke the reader’s food for thought, and simply ends with the question: “What kind of world do we want?” That is the question!

To conclude, who should read this book, which covers the experience of an entire professional life? Readers of all ages who wish to better understand the history and advances of this science and technology that constitutes computer science (we are now talking about digital technology). There is no need for advanced knowledge to immerse oneself in reading (no equations, no complex diagrams, etc.), just common sense and curiosity! I would also recommend it to students in disciplines other than computer science; they will discover an interesting synthesis and perceive reality through the experiences of a real computer scientist. I believe that computer science students would also benefit from reading this book, which will give them, especially in the last chapters, an idea of the great challenges in computer science and may help them in their future professional choices!

Jean-Pierre BANÂTRE
Computer Scientist
Honorary Professor at the University of Rennes 1