I seek the name and any possible information about an artist in the
1960's who conducted these walks, where he followed someone
(unbeknownst to the walker).  I am not sure of all the details to the works.
 I am a graduate student writing a paper on Janet Cardiff and was
hoping to make a compare/contrast between the two.  I can't remember
the guy's name (he was mentioned to me as an avenue to pursue)  If you
can help thank you so much!!!

Hello.

It sounds like you're describing conceptual artist Vito Acconci.

"In 1969, Vito Acconci made Following Piece, in which he pursued a
randomly selected individual from the street, and, like a private eye,
documented his or her movements and activities until they entered a
private place."
source:
New York Arts Magazine
http://nyartsmagazine.com/62/urges.htm

Also see:
Vito Acconci : »Following Piece«, 1969
[Oct. 3-25, 1969, Activity, "Street Works IV?-Program, organized by
the Architectural League, New York]
http://hosting.zkm.de/ctrlspace/d/texts/01?print-friendly=true

This page from USF.edu has a photo of Acconci in action and also
mentions Janet Cardiff.
http://cam.arts.usf.edu/Walkways/WalkWays.html
------

search strategy:
"following strangers" artist

I hope this is the artist whom you're seeking. If not, please let me
know via the "request clarification" feature. Thanks.

Wow!  Thank you so much!  This answer was quick!  It was also very
thorough, giving me three different sources to which to refer! Thanks
again.