Namco Museum refers to the series of video game compilations released by Namco for various 32-bit and above consoles, containing releases of their games from the 1980s and early 1990s. Namco has continued releasing compilations spanning over a decade (1995 to 2010).
The series began on the PlayStation with the tentatively named Namco Museum Volume 1, indicating Namco's intent to make further installments of the series. The series ran until Volume 5 on the PlayStation, covering various games from the late 1980s, before moving onto the Nintendo 64, and all of the sixth generation and seventh generation systems.
Source: Wikipedia, "Namco Museum," available under the CC-BY-SA License.