The text discusses pseudonymization in MongoDB, a data management procedure that replaces personally identifiable information fields with artificial identifiers. To achieve this, views are used to create read-only projections of existing collections or other views. The article provides an example using the Game of Thrones characters collection, where it creates a view called "charactersNoSpoil" that hides sensitive data such as character status. The view is created by leveraging an aggregation pipeline and uses indexes from the master collection. To enforce access control, roles are assigned to users, allowing only authorized personnel to read or write to the view and the underlying collection. The article also explains how to audit the access and actions on the view using MongoDB's auditing feature.