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This study reports vacuum ultraviolet circular dichroism (CD) measurements on (+)-3-methylcyclopentenanone vapor using synchrotron radiation as a light $source.1$ The spectrum will be presented from 2050A to 1325A. The valence shell spectra of ketones are poorly understood. The first three regions of intense CD occur at 3030A, 1960A and 1666A. only the assignment of the $n-\pi \ast$ transition which falls in the 3030A-2780A region, is not questioned. The 1960A region has been previously assigned as $n-\sigma \ast ,\sigma -\pi \ast ,n2-\pi \ast ,\pi -\pi \ast$ and $n-3s$ $(Rydberg)2$. Recent results from electrochromism, showed the electronic transition moment for this transition to be consistent with an $n-G\ast$ or $n-3s$ assignment. Based on polarizability results the electrochromism studies favored the $n-3s$ assignment. However, there are indications that there may be two transitions in this region. The third region of intense CD at 1666A has been assigned as n=d(Rydberg) and $\pi -\pi \ast ,2$ We calculate theoretical rotational strenghts and compare them to experimental values. The results are used to further understand the spectra of ketones. The results indicate that the circular dichroism of the 1960A bond arises from the $n-o\ast$ transition and that an assignment of $\pi -\pi \ast$ is consistent with the circular dichroim at 1666A. In addition, the results indicate which polarizabilities should be used in rotational strength calculations.