How the World Flows acts like a microscope that pulls the reader into the barely noticeable, Lilliputian world of fluids at small scales--the microfluidic world-and answers the question "What is microfluidics?" in non-technical language. Microfluidics is the field of science that studies fluids constrained to spaces that are smaller than one millimeter wide, and by extension, the engineering field which builds devices that exploit the unique properties of fluids at these scales. Author Albert Folch explores this micro science which has inspired engineers to build devices such as engines, spray cans, ballpoint pens, inkjet and 3D printers, pregnancy and Covid tests, glucometers, asthma nebulizers, kidney dialysis machines, and DNA analyzers. This book also shows that many processes essential to life on Earth - such as the formation of raindrops, the rise of sap in plants, and the percolation of water through soil - are all microfluidic marvels. It examines how our cells breathe, feed, and fight diseases through small capillaries. Many ancient human inventions, ranging from soaps and sauces to the candle wick, the gauze, and the ink brush, rely on microfluidics, but the size of the fluid interactions in these systems, natural and human-made, has prevented most people from appreciating their inner workings. Through engaging and digestible stories, Folch takes a lens to this tiny science and demonstrates how big a role microfluidics play in life as we know it.

"This book weaves together personal stories, explanations of natural phenomena, and technological innovations to bring to life the invisible cosmos of tiny droplets of fluid that deeply influence so many phenomena in our world. Readers will be both entertained and fascinated by Folch's revelations about the microdroplets that drive rainbows and monsoons, or the microscopic channels that fuel plants, people, and covid tests. I found it impossible to put down." - Siddhartha Mukherjee, MD, DPhil, Pulitzer Prize-winning author of The Emperor of All Maladies (2011)

"How the World Flows makes a significant contribution to the field of microfluidics. It will become a reference work for those seeking a comprehensive introduction, as well as for teachers and experts." - Jacques Fattaccioli, PhD, Department of Chemistry, École Normale Supérieure and Institut Pierre-Gilles de Gennes

"Folch's new book is a dazzling exploration of the myriad ways that microfluidics underpins our world. Above all, this feels like a book that could convince you to become an engineer if you read it at a young enough age. It could also remind you at any age of the sheer intricacy and wonder of any object when you put it under a microscope. It overflows with curiosity." - Karmela Padavic-Callaghan, New Scientist