It is commonly accepted the attribution of the 'ambient' expression, as a musical genre, to British composer and producer Brian Eno. His album Music for Airports (1978) is considered the first ambient work in history and its liner notes included a "manifesto of the ambient music":
"Ambient Music must be able to accomodate many levels of listening attention without enforcing one in particular; it must be as ignorable as it is interesting."
Eno coined the ambient term to distinguish his minimalistic music aproach from what was despectively called muzak, tinned or background music. In front of that, the idea of ambient started by the British musician was about musical compositions which demand an active listening. He separated himself also from the musique d'ameublement concept, exposed by Erik Satie in 1917.
The development of modular synthesizers and the work of groups such as Tangerine Dream opened, during the 70's, the door to new forms of musical experimentation more related to the creation of atmospheres and the sounds' timbral qualities than to the traditional ways of composition. Due to that flexibility, ambient is very permeable to the influence of other genres.
During the 80's decade, it lived through a period of scarce relevance and was practically absorbed by the new-age movement generated in USA. From that time there are barely some albums to rescue, such as Don Robertson's Spring (1983). However, the genre regained a cult status at the beginning of the 90's, mainly due to its fusion with the electronic music that started to play at the London club scene. Aphex Twins (Selected Ambient Works Volume II, 1994), The Future Sound of London (Lifeforms, 1994) or Autechre (Incunabula, 1993) made ambient popular while mixing it with their own styles, producing multiple subgenres: ambient techno, ambient house, ambient dub, ambient trance...
In 1997 was published what is probably the second milestone in the history of ambient: Substrata, by Norweigian Gair Jennsen, best known as Biosphere. Aside from being an instant classic, this album returned to a more pure ambient and linked to nature, even taking elements from it as samples. It also moved the ambient scene center of attention to northern Europe. Musicians as Swedish Carbon Based Lifeforms (Twentythree, 2011), Solar Fields (Until we meet the sky, 2011) or Biosphere himself set out a sonic space which induces to calm and deep thought.
Ambient has never been a commercially successful genre. Its compositions rarely fit to radio timing and it has been often criticized as "boring" or "too intellectual". However, it has also gained respect and has been acclaimed by specialized critics. It has its own festivals, like the Extreme Chill-Undir Jökli in Hellissandur (Iceland) or the Ambient Music Conference in Helsinki (Finland).