Wikipedia has a pretty good entry for cassettes.
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Lou Judson
Sent: Tuesday, January 25, 2011 3:09 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Of interest -- cassettes hit the US market,
Here in America I was using cassettes regularly in 1971. I had a primitive
Sony that I carried on my bicycle while commuting to work...
But then, I have only ever seen three 8-track decks in my whole life!
My girlfriend's father had a four track deck in his car in the late 1960s.
On Jan 24, 2011, at 7:00 PM, David Breneman wrote:
1968? Wow. The first time I saw a cassette player in a car was in Germany
in 1976. I didn't see cassettes start to make inroads on the 8-Track until
at least 1977. And mass-produced cassettes sounded worse than 8-Tracks
until Dolby gained currency in, when? - I guess around 1978.
It's interesting that these pages say up front that they are sponsored by
Philips/Norelco. Maybe they were seeing things as rosy for the cassette a
little earlier than an objective reporter would have.