Do you often lose your keys? You will find in this book the best strategy to find them, or at least the one deduced from statistical physics. What is the link with biology? Some proteins use the same strategy to find their target inside a living cell. This example illustrates one of the many links between physics and biology. These links result from an intense research activity in the past years at the interface between those two disciplines. This book describes some of the most recent progresses at this interface: from instrumental progresses used in biology to the mechanical description of a cell, to molecular motors, from brain activity mechanisms to auditory or sensory perception. Many fields are covered from the molecular to the scale at the organ level. A few biological notions are presented in the first chapter that may help to access the biological aspects of the others. In the end this book may interest people passionate in science, from the simple amateur to the advanced researcher level.