  In this paper we give a review of the Bowen fluorescence survey, showing that
narrow emission lines (mainly NIII and CIII lines between 4630 and 4660 A)
appear to be universally present in the Bowen blend of optically bright low
mass X-ray binaries. These narrow lines are attributed to reprocessing in the
companion star giving the first estimates of K_2, and thereby providing the
first constraints on their system parameters. We will give an overview of the
constraints on the masses of the compact objects and briefly highlight the most
important results of the survey. Furthermore, we will point out the most
promising systems for future follow-up studies and indicate how we think their
estimates of the component masses can be improved.
