I saw the following question from the "Problem Section" in Schoen and Yau, page 281, problem 12:


Let $M\_1, M\_2$ each have negative curvature. If $\pi\_1 (M\_1)=\pi\_1 (M\_2)$, prove that $M\_1$ is differeomorphic to $M\_2$. 


The authors then commented:
"
There is some progress due to Cheeger, Gromov, Farrell and Hsiang. Cheeger proved that $\pi\_1(M)$ determines the second Stiefel bundle of $M$. Gromov proved $\pi\_{1}(M)$ determines the unit tangent bundle of $M$. Farrell-Hsiang proved $\pi\_{1}(M)$ determines $M\times \mathbb{R}^{3}$. Farrel-Hsiang have only to assume that one of the manifolds has negative curvature."


Here the paper due to Cheeger&Gromov is [this one](http://retro.seals.ch/cntmng?pid=ensmat-001:2000:46::224). I am unable to find any reference on Farrell&Hsiang's work as the book says it was to be published. May I ask if there is any significant progress on this problem? This is obviously some strong rigidity theorem (if turned out to be true). A quick "scan" of the papers involved in the end of Gromov's paper did not reveal anything particularly relevant. 



Is there any progress on Problem 12 (from Schoen and Yau)?
Counter-example was constructed by T.Farrell and L.Jones, in "Negatively curved manifolds with exotic smooth structures", JAMS 1989, volume 2, number 4.


