Vibrational relaxation, incubation times, and unimolecular dissociation of C4H4O have been investigated over the extended temperature range 500-3000 K in 2-5% furan-krypton mixtures, 2% furan-neon mixtures, and in pure furan. The experiments were performed in shock waves using laser-schlieren (LS) densitometry and time-of-flight (TOF) mass spectrometry. At low temperatures and low pressures, only vibrational relaxation was observed using the LS technique. This relaxation is unexpectedly slow and shows a strong nonexponential time dependence. Unimolecular dissociation is observed in TOF experiments between 1300 and 1700 K in a pressure range of 175-250 Torr as well as LS experiments between 1700 and 3000 K for pressures between 100 and 600 Torr. The TOF experiments show that under the given conditions two molecular dissociation channels leading to C2H2 + CH2CO or to C3H4 + CO are dominant. The branching ratio between these channels has been determined between 1300 and 1700 K. At low temperatures, the molecular channel leading to C3H4 and CO is preferred, but a channel switching was observed around 1700 K. The domination of these molecular channels is consistent with the shape of the LS profiles, and these have been successfully modeled with just these two reactions. The overall unimolecular rate constant is in the falloff regime close to the low-pressure limit. By use of statistical reaction rate theory, the total unimolecular rate constant could be modeled over an extended temperature and pressure range using a value of [Delta E](all) = 50 cm(-1) for the furan dissociation. In a small range of conditions at low pressures and high temperatures, both the vibrational relaxation and dissociation were resolved and incubation times estimated.