Proteins are an important class of biological macromolecules present in every biological organism. Proteins are synthesised on ribosomes as a linear chain of amino acid residues in a specific order from information encoded within the DNA. In order to function, each newly synthesised chain must fold into the unique 3-D structure that is characteristic of the individual protein. Protein folding is a highly specific process and each protein has a specific fold to perform its specific function. Uncovering the mechanisms through which such processes take place is one of the greatest challenges in the post genomic era. This book presents current research from around the globe in the study of protein folding, including heterologous protein folding in yeast; how homodimeric proteins fold and assemble; ribosome assisted protein folding; protein disulphide isomerases; and self-assembling peptids for biomedical applications.