This biomedical engineering core junior unit of study provides an introduction to the relatively recent, and rapidly growing, biotechnology industry, with a focus on the current key commercial applications. In the 1990s, the word 'biotech' entered our lexicon as a synonym for overnight investment wealth. The biotechnology acronym GM (genetically modified) also entered our lexicon in the 1990s. Biotechnology can be broadly defined as the commercial exploitation of biological processes for industrial and other purposes. A significant focus for commercial activities has been GM technology: GM microorganisms, plants, animals, and even humans (gene therapy). The 'biotech industry' arose rapidly in the late 20th century, and is now one of the largest industries in the world, and is one of the cornerstones of the global biomedical industry which comprises three main sectors: Medical Devices, Pharmaceuticals, and Biotechnology. Significant global commercial biotechnology activity concerns the manufacture of therapeutic compounds from GM microorganisms using bioreactors, for example insulin. Another significant sector is agricultural: 'agri-biotech' which concerns GM higher lifeforms (plants and animals) primarily for the food industry, and also other industries such as the energy industry (biofuels). The third sector concerns therapeutic GM of humans, known as 'gene-therapy'. Some other important biotechnologies will also be explored including monoclonal antibodies, genome sequencing and personalised medicine, and RNA-interference technology (RNAi).