  We study the stability, form and interaction of single and multiple dark
solitons in quasi-one-dimensional dipolar Bose-Einstein condensates. The
solitons are found numerically as stationary solutions in the moving frame of a
non-local Gross Pitaevskii equation, and characterized as a function of the key
experimental parameters, namely the ratio of the dipolar atomic interactions to
the van der Waals interactions, the polarization angle and the condensate
width. The solutions and their integrals of motion are strongly affected by the
phonon and roton instabilities of the system. Dipolar matter-wave dark solitons
propagate without dispersion, and collide elastically away from these
instabilities, with the dipolar interactions contributing an additional
repulsion or attraction to the soliton-soliton interaction. However, close to
the instabilities, the collisions are weakly dissipative.
