  We present precise photometry of the pulsating Herbig Ae star HD 142666
obtained in two consecutive years with the MOST (Microvariability & Oscilations
of STars) satellite.
  Previously, only a single pulsation period was known for HD 142666. The MOST
photometry reveals that HD 142666 is multi-periodic. However, the unique
identification of pulsation frequencies is complicated by the presence of
irregular variability caused by the star's circumstellar dust disk. The two
light curves obtained with MOST in 2006 and 2007 provided data of unprecedented
quality to study the pulsations in HD 142666 and also to monitor the
circumstellar variability.
  We attribute 12 frequencies to pulsation. Model fits to the three frequencies
with the highest amplitudes lie well outside the uncertainty box for the star's
position in the HR diagram based on published values.
  The models suggest that either (1) the published estimate of the luminosity
of HD 142666, based on a relation between circumstellar disk radius and stellar
luminosity, is too high and/or (2) additional physics such as mass accretion
may be needed in our models to accurately fit both the observed frequencies and
HD 142666's position in the HR diagram.
