lead up to vs preface

lead up to

verb
  • To follow or mark a path toward. 

  • To set in motion; to act as a causal or preparatory event or sequence of events. 

  • To precede in time. 

preface

verb
  • To give a preface to. 

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

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. 

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