When there is qualitative information about the underlying professes a
nd structure of a dynamical system, it may be possible to infer very a
ccurate quantitative information about these processes using only an o
utput rime series from the system. We illustrate how this can be accom
plished for time series data from a delay-differential equation with a
single fixed delay. Our approach exploits modem techniques for non-pa
rametric function estimation, is robust to fairly high levels of dynam
ic noise and measurement error, and can be extended straightforwardly
to more general delay-differential systems and multivariate systems.