Chemical engineering as it is known today — in which theoretical models are used to design and maintain processes — bears only a slight resemblance to the nascent field. In its beginnings, chemical engineering involved the dissection of chemical processes into unit processes and unit operations using mostly empirical methods. Material and energy balances soon entered the scene in the late 1920s, followed by the introduction of transport phenomena. While many scientists and engineers contributed to the evolution of chemical engineering, one man in particular stands out. Neal Russell Amundson, who became a full professor of chemical engineering at the Univ. of Minnesota at the age of 35, can be credited for the proliferation of scientific content within the chemical engineering field and profession.