While radio observations of the Sun have mostly focused on active region phenomena, they also contribute unique data to our knowledge of the quiet Sun, in particular through accurate measurements of the temperature as a function of height in the atmosphere and through the measurement of nonthermal emissions from chromospheric and coronal heating events. Here we review observations of the quiet Sun using radio telescopes and discuss current science problems that will be addressed with future facilities such as the Frequency Agile Solar Radiotelescope (FASR).