Here's why:
* Encyclopedia entries and other reference works are often authored by multiple contributors or have no listed author. Therefore, it's common to cite the entry by its title instead of a specific author.
* MLA format prioritizes the source title and publication information when an author is not available.
Here's a typical MLA citation for an encyclopedia entry:
"Entry Title." *Encyclopedia Title*, edition number, publisher, year published, page numbers.
Example:
"Quantum Mechanics." *The Oxford Encyclopedia of Physics*, 2nd ed., Oxford University Press, 2010, pp. 250-275.