In MLA style, when you cite a summary of a work, you should generally mention the name of the work you are summarizing and its author in your prose and include the work in your works-cited list. The author’s name in your prose will direct the reader to the works-cited-list entry. Page numbers are not normally needed, since you are discussing the work as a whole rather than quoting or paraphrasing a passage from it:

In Obedience to Authority, Stanley Milgram argues that people who are normally kind to others will act otherwise when they are under the influence of a person in a position of power. He recounts the results of an experiment in which people who were asked to deliver electric shocks to others not only agreed to do so but also continued to do so even when it was clear that those receiving the shocks were in pain. Milgram concludes that the further down the chain of command people are, the less likely they are to take responsibility for their actions.

Work Cited

Milgram, Stanley. Obedience to Authority: An Experimental View. Harper Perennial, 2009.