In order to fully grasp an author's "cogito", it is important to examine all available examples of the author's work. For Poulet, letters, journals, and unpublished manuscripts hold as much information about the author's "cogito" as published novels or poems (Leitch et al. 1318). He did not believe that these sources should be analyzed as objects, however. Instead, they should be used by the reader to "coexist with the author's developing grasp and formulation of his own existence" (Lawall 112). By examining an author's complete body of work, the critic begins to see patterns of expression not only in the work of one particular author but also across literary periods.