  The primary purpose of this paper concerns the relation of (compact)
generalized manifolds to finite Poincar\'{e} duality complexes (PD complexes).
The problem is that an arbitrary generalized manifold $X$ is always an ENR
space, but it is not necessarily a complex. Moreover, finite PD complexes
require the Poincar\'{e} duality with coefficients in the group ring $\Lambda$
($\Lambda$-complexes). Standard homology theory implies that $X$ is a
$\mathbb{Z}$-PD complex. Therefore by Browder's theorem, $X$ has a Spivak
normal fibration which in turn, determines a Thom class of the pair
$(N,\partial N)$ of a mapping cylinder neighborhood of $X$ in some Euclidean
space. Then $X$ satisfies the $\Lambda$-Poincar\'{e} duality if this class
induces an isomorphism with $\Lambda$-coefficients. Unfortunately, the proof of
Browder's theorem gives only isomorphisms with $\mathbb{Z}$-coefficients. It is
also not very helpful that $X$ is homotopy equivalent to a finite complex $K$,
because $K$ is not automatically a $\Lambda$-PD complex. Therefore it is
convenient to introduce $\Lambda$-PD structures. To prove their existence on
$X$, we use the construction of $2$-patch spaces and some fundamental results
of Bryant, Ferry, Mio, and Weinberger. Since the class of all $\Lambda$-PD
complexes does not contain all generalized manifolds, we appropriately enlarge
this class and then describe (i.e. recognize) generalized manifolds within this
enlarged class in terms of the Gromov-Hausdorff metric
