conclusion vs preface

conclusion

noun
  • The end or close of a pleading, for example, the formal ending of an indictment, "against the peace", etc. 

  • The outcome or result of a process or act. 

  • In an argument or syllogism, the proposition that follows as a necessary consequence of the premises. 

  • A decision reached after careful thought. 

  • An estoppel or bar by which a person is held to a particular position. 

  • The end, finish, close or last part of something. 

preface

noun
  • An introduction, or series of preliminary remarks. 

  • A title or epithet. 

  • The beginning or introductory portion that comes before the main text of a document or book. 

  • The prelude or introduction to the canon of the Mass. 

verb
  • To give a preface to. 

  • To introduce or make a comment before (the main point). 

How often have the words conclusion and preface occurred in a corpus of books? (source: Google Ngram Viewer )