Searches for unstable neutral and charged heavy leptons. N and L+/-. and fo
r excited states of neutral and charged leptons, v*, e*, mu*, and tau* have
been performed in e(+)e(-) collisions using data collected by the OPAL det
ector at LEP. The data analysed correspond to an integrated luminosity of a
bout 58 pb(-1) at a centre-of-mass energy of 183 GeV, and about 10 pb(-1) e
ach at 161 GeV and 172 CeV. No evidence for new particles was found. Lower
limits on the masses of unstable heavy and excited leptons are derived. Fro
m the analysis of charged-current, neutral-current, and phototonic decays o
f singly produced excited leptons, upper limits are determined for the rati
o of the coupling to the compositeness scale, f/A, for masses up to the kin
ematic limit. For excited leptons, the limits are established independently
of the relative values of the coupling constants f and f'.