Ever have I been sought out,
By one stone searching round about, ("one stone" = EINSTEIN) (Guessed by Gaberax)
And yet elusive I remain
To one stone and to every brain.
When kin do come to visit you (general) RELATIVITY (Guessed by Jon)
They have a spat, they truly do
With those you've paid to fix your car, (quantum) MECHANICS (Guessed by SigTauGimp)
Thus we've arrived at where we are.
The cat's toy sought to make amends STRING (theories) (Guessed by Gaberax)
But could not make the two be friends
as it was five--oh tragic day
When fivefold did it split away.
But now have I come into view
The thirteenth and to those of you
Who seek me out, the final piece
In this great puzzle--gain release.
M-THEORY (Guessed by Gaberax)