  We suggest a modified and briefer version for the proof of Higman's embedding
theorem stating that a finitely generated group can be embedded in a finitely
presented group if and only if it is recursively presented. In particular, we
shorten the main part of original proof establishing characterization of
recursive relations in terms of benign subgroups in free groups. Also, some
technical lemmas on homomorphisms are replaced by simple combinatorial
observations on words in free constructions.
