Human Agency in a Digital World - by Marcus Fontoura (Paperback)

Book Synopsis

This may be the first true AI-era self-help book--not because we need help using technology, but because we need help using it well. It's about building the knowledge--and the confidence--to question, to evaluate, to choose. Because understanding how algorithms work is the first step in making sure they work for us.

Human Agency in a Digital World is a book about reclaiming our role--not as passengers, but as pilots--in the fast-moving journey of technological change. Written by a computer scientist who is also a father, a teacher, and a lifelong student of how things work, this book is a deeply personal and accessible guide to the systems shaping our lives--and how we might shape them back.

We are surrounded by digital agents. They suggest the next song, answer our questions, sort our emails, recommend what to watch, and--often invisibly--shape what we think. But what do we know about them? And how much power do we really have to question, understand, or even redirect their impact?

In this book, Marcus Fontoura explores the hidden architectures of modern life--from social media and search engines to cloud computing, AI, and quantum technologies--uncovering both how they work and what they mean. Drawing from decades of experience building the backbone of the internet and cloud platforms, he demystifies the core concepts that govern today's systems and offers readers a way to develop digital fluency without needing a computer science degree.

But this is not just a book about machines. It's a book about people-about how we use efficiency not just to optimize for speed or cost, but to unlock creativity, opportunity, and well-being. With examples ranging from broken playlists to protein folding, and reflections that move fluidly between systems thinking and everyday life, Digital Agency asks us to consider a simple but profound question: what do we want technology to do for us, and what will we do with it in return?

Review Quotes

"As someone who has built real-world systems, from large-scale search engines to AI-driven healthcare platforms, I found Human Agency in a Digital World to be both timely and refreshingly grounded. The book argues that understanding technology is no longer a niche technical skill but a form of modern literacy, essential for navigating everything from algorithms to social infrastructure.

What distinguishes this book is its lens: it frames computing not as magic, but as a vehicle for efficiency and human agency. It sidesteps both techno-optimism and fear-mongering, focusing instead on how digital systems, search, cloud, AI, even quantum computing, can augment human capabilities, but only if guided by intentional, values-driven choices. The taxonomy of physical systems, physically-backed myths, and digital-only myths is especially insightful, and is a mental model I now find myself using when evaluating both technologies and organizations.

The writing is accessible, often witty, and never talks down. From the cautionary tale of NASA's Mars Climate Orbiter to the absurdity of bogosort, the book distills technical depth into vivid, memorable stories. If anything, the breadth occasionally comes at the expense of depth in later chapters, but that tradeoff is purposeful. This isn't a technical manual, it's a call to understand enough to steer.

For technologists, educators, policymakers, and curious citizens alike, Human Agency in a Digital World is not just a guide to the systems shaping our lives, it's a reminder that those systems remain ours to shape."--Kira Radinsky, Cofounder and CTO at Diagnostic Robotics

"Imagine a book where you learn how complex things work through stories, movie characters, books, and memories drawn from your own imaginary world. That book exists. Human Agency in a Digital World, by Marcus Fontoura, invites you on a journey where imagination meets insight, making the digital age feel personal, accessible, and alive.

Tracing the evolution of digital technologies--from the earliest concepts of computing to the rise of artificial intelligence--this book helps readers understand that technology isn't magic, but the product of human ingenuity. Behind every digital artifact are scientists, engineers, and creators whose work drives progress and shapes the world we live in.

At a time when digital technologies and algorithms deeply influence our lives, Marcus Fontoura's book offers timely insight into their dilemmas, complexities, and promises. I commend the author for his inclusive and engaging approach to unveiling the intricacies of technology for the lay reader. This book sits at the heart of today's most pressing debates about the digital world."--Virgilio Almeida, Faculty Associate at Berkman Klein Center for Internet and Society, Harvard University. Author of Algorithmic Institutionalism

"Information technology is having both a positive and negative impact on everyone on this planet. This book provides a fascinating overview of this effect by making knowledge of computer technology and its impact on society accessible to a broad segment of society." --Donald Cowan, Distinguished Professor Emeritus of Computer Science, University of Waterloo, Canada

"What Marcus Fontoura has done with Human Agency in a Digital World is an intellectual tour-de-force illuminating both the origins of our digital transformation, the patterns behind these changes, and the way our lives might evolve to embrace what might initially be a more complicated future, but ultimately becomes a simpler form of abundance.? The way Marcus draws analogies between diverse topics such as Daniel Kahneman's work, computer programming, and neural networks exposes something rare: it shows us how the greatest systems thinkers who have been powering the transformation to the internet, mobile, the cloud, search, and now AI, have been actively fusing concepts from everywhere.

In the same way large language models have slurped up all the information on the web, deep thinking distinguished engineers at the top technology companies have used the power of the web to explore concepts far and broad, fusing them back into products and technologies to benefit our lives. No where is that on better display than in this book. You will find yourself coming back over and over again to sections and chapters as the web of intellectual connections unveils itself." --Brad Porter, Founder and CEO of Cobot. Formerly Distinguished Engineer for Amazon leading robotics and CTO for Scale AI.

"With the rising importance of software and artificial intelligence in our world, it's increasingly important for everybody to understand how this new technology works, to demystify algorithms, and to democratize understanding of computer systems. Marcus Fontoura's Human Agency in a Digital World does a fantastic job of explaining complex concepts in simple terms, to make computer science topics approachable for anybody who would otherwise be intimidated to learn."--Hadi Partovi, Founder and CEO at Code.org

About the Author

Marcus Fontoura is currently in his second tenure as Technical Fellow and Corporate Vice President at Microsoft, where he works as CTO for Azure Core.

Most recently, he was the CTO at Stone (2022-2025), where he led the engineering organization, focused on building highly efficient financial platforms and an amazing engineering culture. He continues to serve as an advisor to the company.

Previously, in his first tenure as Technical Fellow and Corporate Vice President at Microsoft (2013-2022), Marcus worked as the chief architect for Azure Compute and led the Azure efficiency team. Marcus also had posts at Google, Yahoo, and IBM Research.