The 'Create' command is used in SQL to define a new structure in a database, such as creating a new table to store data. In the context of the question, this is the command that directly allows the creation of a new structure where information about books can be stored. The 'Alter' command is used to modify an existing structure, and the 'Drop' command is used to remove existing structures. The 'Permissions' command does not directly relate to the creation of structures but instead deals with the authorization aspect of databases.