The Vietnamese term bụi đời ("dust of life") refers to vagrants in the city, or, trẻ bụi đời to street children or juvenile gangs. From 1989, following a song in the musical Miss Saigon, "Bui-Doi" came to popularly refer to Amerasian children left behind in Vietnam after the Vietnam War.
Rural poor coming to the towns
The term bụi đời ("dust of life") originally referred to the starving people of the countryside taking refuge in towns, in the 1930s. The term trẻ bụi đời "young vagrants," now refers to street children or juvenile gang members. It is intended to bring to mind an image of a child abandoned and moving about without purpose, like dust. In Vietnamese, it has no racial connotation. Vietnamese refer to Amerasians as Mỹ lai (mixed American and Vietnamese), con lai (mixed-race child), or người lai (mixed-race person).
The connection to mixed-race parentage given in Western media, from connection with Miss Saigon, is not widely known in Vietnam today. The term bụi đời in Vietnam today refers to any people, but usually young men, who live on the street or live as wanderers. A related verb đi bụi ("go dust") means someone who has left their home, usually due to arguments with their family, to take on the bụi đời wandering or street life.
Miss Saigon and Amerasian orphans
In the West, the term Bui-Doi became widely known from the use in the dialogue, and particularly the song title "Bui-Doi", of the 1989 musical Miss Saigon by Claude-Michel Schönberg and Alain Boublil, which opened 1991 on Broadway and until its closing in 1999 was the eleventh longest running Broadway musical in musical theatre history. The song "Bui-Doi" had lyrics written by Alain Boublil and Richard Maltby, Jr. They took the term bụi đời to mean not Vietnamese street children, but the Amerasian offspring of American soldiers and Vietnamese mothers abandoned at the end of the Vietnam War.
Mixed race children in Vietnam
The majority of mixed race people after the Vietnam war were Amerasians or children of Vietnamese mothers and military or civilian men from the United States. Amerasians born during the Vietnam War (1964–75) could be the issue of anything from long-term unions to rape. Because of the large sex industry brought on by the military economy, Amerasians are predominantly seen as off-spring of GI fathers and prostitute mothers. Life was frequently difficult for such Amerasians; they existed as pariahs in Vietnamese society. Often, they would be persecuted by the communist government and sometimes even sold into prostitution as children. Under the Amerasian Homecoming Act of 1988, a Vietnamese Amerasian could obtain a U.S. visa on the basis of appearance alone. Amerasians gained the attention of con artists who claimed to be their relatives in the hope of obtaining visas. About 23,000 Amerasians immigrated to the U.S. under this act.
In the United States, bui doi, or the term "dust of life", again referred to the criminal class, where the youths included newly transplanted Vietnamese and Amerasians. The misuse of the word bui doi also migrated to the United States and was appropriated by the mainstream.
In popular culture
"Straight to Hell", a 1982 song by The Clash, deals with the problem of Amerasian children in Saigon. But the lyrics "When it's Christmas out in Ho Chi Minh City, Kiddie say papa papa papa papa-san take me home", etc., make no mention of the term "bui doi."
The 1977 made for TV movie "Green Eyes" was a fictional movie about an American veteran who makes a trip back to Southeast Asia to search for his son from a liaison with a Vietnamese woman. He encounters a boy with green eyes who insists that he must be half American and thus eligible to go to America. 
The 1994 documentary film Bui doi: Life Like Dust uses the term to describe Ricky Phan, a Vietnamese refugee who turned to a life of crime after escaping from Vietnam to California.
The 2004 movie The Beautiful Country depicts the life of a fictional bui doi and his efforts to become reunited with his American father. The prologue to The Beautiful Country opens with a definition: “Bui Doi: “less than dust” Term used to describe Vietnamese children with American fathers.”
- Theater Yearbook 1990-1991: The Complete Broadway and Off-Broadway ... - Page 26 Otis L. Guernsey, Jeffrey Sweet - 2000 "Nowhere is the dichotomy of good intentions and cheesy realization more blatant then in the song "Bui-Doi," an appeal on behalf of the outcast, half-breed illegitimate offspring Americans left behind in Southeast Asia."
- Philippe M. F. Peycam - The Birth of Vietnamese Political Journalism: Saigon, 1916-1930 Page 24 2012 "Often referred to as bụi đời [dust of life], they were described by the communist newspaper of the 1930s, La Lutte, as the “starving people from the countryside taking refuge in towns.” 42 Owing to the lack of heavy industry, ...
- Matthew Bernstein, Gaylyn Studlar Visions of the East: Orientalism in Film - Page 167 1997 "Here, the character John (an army friend of the male lead) stands facing the audience in front of a lectern on a dimly lit and bare stage. As he sings the number "Bui Doi" (dust of life), a collage of children's images is projected onto ...."
- The Theater Mania guide to musical theater recordings - Page 244 Michael Portantiere, TheaterMania.com (Firm) - 2004 "The French-speaking librettist Boublil's collaboration with Richard Maltby, Jr. yielded lyrics that are awkwardly ... Although it's difficult to pick the nadir of the score, a good candidate is "Bui Doi," a shamelessly manipulative plea on behalf of ..."
- R. Andrew Lambert Beginning a Prayer Life Page 18 - 2009 "In Vietnam, children like me (Amerasians) were called Bụi Đời “dust of life” and we were hated and ostracized by Vietnamese society. I was left with another Vietnamese family for which my mother was to regularly pay what she could."
- Benge, Michael (22 November 2005). "The Living Hell of Amerasians". FrontPage Magazine. Retrieved 8 January 2011.
- Surviving twice: Amerasian children of the Vietnam War By Trin Yarborough, p. 103.
- The bubbling cauldron: race, ethnicity, and the urban crisis By Michael P. Smith, Joe R. Feagin, p. 68.
- Soil and Culture - Page 92 Edward R. Landa, Christian Feller - 2010 "The prolog to The Beautiful Country (2004) is a definition: “Bui Doi: “less than dust” Term used to describe Vietnamese children with American fathers” The film follows such a Vietnamese young man, Binh, from his escape from Vietnam to the "
- The song "Bui Doi" from the musical Miss Saigon (1989). Sung by Peter Polycarpou. Lyrics by Alain Boublil. Music by Claude-Michel Schonberg.