  In this paper we review the role of the neutron lifetime and discuss the
present status of measurements. In view of the large discrepancy observed by
the two most precise individual measurements so far we describe the different
techniques and point out principle strengths and weaknesses. In particular we
discuss the estimation of systematic uncertainties and its correlation to the
statistical ones. In order to solve the present puzzle, many new experiments
are either ongoing or being proposed. An overview on their possible
contribution to this field will be given.
