  Captures of compact objects (COs) by massive black holes in galactic nuclei
(aka ``extreme-mass-ratio inspirals'') will be an important source for LISA.
However, a large fraction of captures will not be individually resolvable, and
so will constitute a source of ``confusion noise,'' obscuring other types of
sources. Here we estimate the shape and overall magnitude of the spectrum of
confusion noise from CO captures. The overall magnitude depends on the capture
rates, which are rather uncertain, so we present results for a plausible range
of rates. We show that the impact of capture confusion noise on the total LISA
noise curve ranges from insignificant to modest, depending on these rates.
Capture rates at the high end of estimated ranges would raise LISA's overall
(effective) noise level by at most a factor $\sim 2$. While this would somewhat
decrease LISA's sensitivity to other classes of sources, it would be a pleasant
problem for LISA to have, overall, as it would also imply that detection rates
for CO captures were at nearly their maximum possible levels (given LISA's
baseline design).

General Relativity and Quantum Cosmology