The Euromech colloquium bearing the number 267 convened at Figueira da Foz (Portugal) on Wednesday, September 19, 1990. The topic (Discrete Models of Fluid Dynamics) was new to Euromech colloquia, but the meeting was, in a sense, a continuation of previous meetings under slightly different titles held in Santa Fe' (New Mexico, 1986) and Torino (Italy, 1988).