Protein aggregates, whether amorphous or structured (amyloid), have attracted much attention in recent years and despite extensive efforts, the mechanism of their formation is poorly understood. While "natural" aggregation (polymerization) of monomers could improve the biological function of some proteins, it is usually the darker side of this phenomenon which is discussed in many studies: deleterious aggregation that could lead to loss of biological activity under in vitro conditions or cause misfolding diseases. In this review, protein aggregation has been overviewed, starting from some general concepts involved in its formation, followed by mentioning studies aimed at elucidation of its kinetics and mechanism, or characterization of intermediates that would be aggregation-prone, and finally, reporting some of the studies related to the design of methods that would control the process. Similarly, amyloid aggregates have been defined, and current methods used in their characterization have been briefly described, with an emphasis on in silico studies. Finally, identification and design of such molecules which may be effective in control of this process is discussed.