A target internalized within a cell (and a binding member that
specifically binds thereto) can be identified in an efficient manner by
segregating (or substantially segregating) genetic material encoding the
binding member from genetic material encoding a binding member that binds
to a target that is not internalized. This can be achieved by employing a
display library of binding members having a genotype/phenotype linkage
via a non-fusion protein format, whereby genetic material encoding
non-in-ternalized targets can be segregated (or substantially segregated)
without lysing the cells. Internalized genetic material subsequently can
be isolated and amplified.