In this book, when fibres in a composite are discontinuous and are shorter than a few millimetres, the composite is called  'short fibre reinforced composite'. That is, short fibre reinforced composites contain discontinuous fibres with a length less than a few millimetres. In most cases, polymers are used as matrices for discontinuous fibre  einforced composites.
     Short fibre reinforced polymer (SFRP) composites  have found extensive applications in automobiles, business machines, durable consumer items, sporting goods and  electrical industries, etc., owing to their low cost, easy processing and their superior mechanical properties over the parent polymers. Extrusion compounding and injection moulding processes are frequently employed to make SFRP composites. The use of these conventional fabrication  techniques to produce large-scale SFRP composite parts makes manufacturing of these composites efficient and inexpensive compared to manufacturing of continuous-fibre reinforced polymer composites, which are fabricated by time-consuming processes, rendering them unsuitable for high volume production. At present, SFRP composites are only one class within a variety of composite materials with a high growth rate due to their extensive applications and comparatively simple manufacturing techniques.