Situated at the forefront ofinterdisciplinary researchon ferromagnetic microwires and their multifunctional composites, this book starts with acomprehensive treatment ofthe processing, structure, properties and applications of magnetic microwires. Special emphasis is placed onthe giant magnetoimpedance (GMI) effect, which forms the basis for developing high-performance magnetic sensors. After defining the keycriteria for selecting microwires for various types of GMI sensors, the book illustrates how ferromagneticmicrowires are employedas functional fillers to create a new class of composite materials withmultiple functionalities for sensing and microwave applications. Readers are introduced tostate-of-the-art fabrication methods, microwave tunable properties, microwaveabsorption and shielding behaviours, as well as themetamaterial characteristics of these newly developed ferromagnetic microwire composites. Lastly, potential engineeringapplications are proposed so as tohighlight the most promising perspectives, current challenges andpossible solutions.