Cassette players were designed by the Phillips corporation in 1963 and sold to the public in 1965. They were originally meant to record vocal dictation but later evolved to replace record players in home entertainment systems.
Cassette players allowed you to in effect "shrink" your music collection as tapes were much smaller in size than records. They also allowed people to record from other tapes, records and the radio which ushered in the age of the "mixed tape."
Cassette players came in four main types, non-moving cassette decks, portable "boom boxes," personal Walkman and car stereo systems.
Cassette players were in popular use from the middle of the 1970s to the 1990s when the rise of CD players began to cut into the cassette player market share.
The introduction of Dolby sound and noise reduction technology greatly improved the audio quality of cassette players as compared to 8 track players and cheaper turntable record players.