This paper describes the latest and (for most products) definitive data set from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS). MLS data have formed the basis of numerous studies, and the version 5 data, produced using more advanced algorithms than earlier versions, represent a significant improvement in quality and scientific applicability for most of the MLS data products. The version 5 data include midstratospheric to lower mesospheric temperature and geopotential height (the latter is a new product from MLS), water vapor from the upper troposphere to the mesosphere, stratospheric and mesospheric ozone, and stratospheric nitric acid, chlorine monoxide, and methyl cyanide (also a new product). The vertical retrieval grid over the stratosphere and lower mesosphere has been doubled, to six surfaces per decade change in pressure (~2.5 km), compared to three surfaces per decade in previous versions. The accuracy and precision of lower stratospheric ozone, chlorine monoxide, and nitric acid have been improved. For each product, a description of relevant changes to the algorithms is given, along with an update on its validation, a description of the accuracy, precision, and vertical resolution of the data, and information on what quality control methods to apply when using the data.