Book excerpt: Protein folding and aggregation is the process by which newly synthesized proteins fold into the specific three-dimensional structures defining their biologically active states. It has always been a major focus of research in biochemistry and has often been seen as the unsolved second part of the genetic code. In the last 10 years we have witnessed a quantum leap in the research in this exciting area. Computational methods have improved to the extent of making possible to simulate the complete folding process of small proteins and the early stages of protein aggregation. Experimental methods h.