  We analyze the mass content of the massive strong-lensing cluster Abell 586
($z = 0.17$). We use optical data (imaging and spectroscopy) obtained with the
Gemini Multi-Object Spectrograph (GMOS) mounted on the 8-m Gemini-North
telescope, together with publicly available X-ray data taken with the
\textit{Chandra} space telescope. Employing different techniques -- velocity
distribution of galaxies, weak gravitational lensing, and X-ray spatially
resolved spectroscopy -- we derive mass and velocity dispersion estimates from
each of them. All estimates agree well with each other, within a 68% confidence
level, indicating a velocity dispersion of 1000 -- 1250 \kms. The projected
mass distributions obtained through weak-lensing and X-ray emission are
strikingly similar, having nearly circular geometry. We suggest that Abell 586
is probably a truly relaxed cluster, whose last major merger occurred more than
$\sim 4$ Gyr ago
