Originally Posted by dpedsea
The tiles have an embossed pattern and have been peeled up/come loose in several areas revealing the sticky concrete below.
Linoleum tiles were used back in the 50's and 60's, and so far as I know, they never had an embossed surface pattern. Also, Peel & Stick tiles have an embossed surface, and often will have a clear adhesive that stays behind on concrete if the tile breaks off.
I'm wondering if what you have now are Peel & Stick tiles?