  Observations in the infrared have played a significant role in the
development of our understanding of WR140. Two sets of observations are
described here: the changing profile of the 1.083-{\mu}m He I line observed for
the 2009 campaign to study evolution of the wind-collision region near
periastron passage, and multiwavelength photometry and imaging of the dust made
by WR140 in previous periastron passages.
