Homelessness emerged as a public concern in the United States in the late 1970s and early 1980s as Americans began encountering people living on the streets, a way of life which had formerly been confined to the skid rows of large cities. By the mid-1980s to early 1990s, the visibly homeless were becoming a common sight even among those countries with well-developed social safety-net programs, such as Canada. Through television and newspaper reporting, people in North America were also aware of the thousands of people living without adequate housing in African, Asian, and South American countries, though, at least initially, these issues were not connected to homelessness "at home." Much of the early discussion of homelessness in industrialized countries centered on the deinstitutionalization of the mentally ill who were so visible on city streets. By the latter part of the 1980s, however, journalists and social scientists began to consider the tearing down of cheap inner-city housing in the form of old hotels and rooming houses (the process of gentrification) as a major explanation for the lack of housing available to the poorest segment of society. In this way, the public discourse on homelessness in the first world moved away from the pathology model to the lack of housing model, and moved closer to explanations long used in the third world.

A widely used and useful conceptualization of homelessness was developed by Peter Rossi (see Rossi et al. 1987: 1336) who distinguishes between the literally homeless (persons who obviously have no access to a conventional dwelling and who would be considered homeless by any conceivable definition of the term) and the precariously or marginally housed (persons with tenuous or very temporary claims to a more or less conventional dwelling or housing). This distinction can be used in studies of the visibly homeless (those in homeless shelters and living on the streets, in encampments, in abandoned buildings, and in places such as subway stations) and the precariously housed (those doubled-up temporarily with other, usually poor, families, or those in inexpensive lodging who pay by the day or week). How widely one casts the "homeless net" has a tremendous impact on the numbers and characteristics of the people included in the definition of homelessness.

Added to the difficulty of people's varying definitions of "homeless," is the fact that cultures have different words for the concept, each with different and sometimes subtle connotations. For example, in Montreal, Quebec, people are variously called les itinérants by the religious and advocacy community (the newspaper sold on the streets of Montreal is L'itinéraire) and sansabri (without shelter) for use within professional and academic circles. Some people have suggested that sans-abri came into vogue in Montrealafter the media attention of the United Nations 1987 International Year of Shelter for the Homeless ( Glasser, Fournier, and Costopoulos 1996). Cultural differences are also in evidence when homelessness is viewed cross-nationally -- one speaks of the roofless of India, the furosha ("floating people") of Japan, and the gamino (street child, from the word "gamin") of Colombia. Different definitions of a home also add to the dilemma of defining homelessness cross-nationally. For example, a person living in a one-room house constructed of mud, sticks, twigs, and branches in a squatter settlement of Nairobi, Kenya ( Settlements Information Network Africa, 1986) would be classified as homeless, or at the very least, the housing would be considered marginal in most parts of the industrialized world. . .