  We present observations of CK Vul obtained with the Spitzer Space Telescope.
The infrared spectrum reveals a warm dust continuum with nebular, molecular
hydrogen and HCN lines superimposed, together with the "Unidentified Infrared"
(UIR) features. The nebular lines are consistent with emission by a low density
gas. We conclude that the Spitzer data, combined with other information, are
incompatible with CK Vul being a classical nova remnant in "hibernation" after
the event of 1670, a "Very Late Thermal Pulse", a "Luminous Red Variable" such
as V838 Mon, or a "Diffusion-induced nova". The true nature of CK Vul remains a
mystery.
