Agglomeration is a natural phenomenon which has been in existence since solids first formed on earth. Soon, animals and later humans made use of agglomeration for a variety of activities. During the two most recent centuries, as technical development accelerated, empirical improvements of-old mechanical techniques still yielded methods and procedures in each of the emerging industries, which solely solved problems within a specific technological field. This resulted in the design of different equipment and systems for similar tasks. They were defined, described and executed in ways that are typical for that particular industry, often with independent attempts to explain the principles and using their own nomenclature. Only after the elaboration of a common theory, the collection of know-how from many different disciplines and the unbiased evaluation of data did the application of this combined knowledge to the needs of all industries lead to the recognition that size enlargement by agglomeration is a unit operation in its own right and qualifies as an independent field of science. The paper describes the history of size enlargement by agglomeration, the various developments and applications that have emerged over the years as well as the new, interdisciplinary approach to consistently and uniformly solve agglomeration problems in the different industries. (C) 2003 Elsevier Science B.V All rights reserved.