  The present paper regards the volume function of a doubly truncated
hyperbolic tetrahedron. Starting from the previous results of J. Murakami, U.
Yano and A. Ushijima, we have developed a unified approach to express the
volume in different geometric cases via dilogarithm functions and to treat
properly the many analytic strata of the latter. Finally, several numeric
examples are given.

Metric Geometry;Complex Variables;Differential Geometry