What are some themes of A series of unfortunate events book thirteenth?
"THEME: A central idea or statement that unifies and controls an entire literary work. The theme can take the form of a brief and meaningful insight or a comprehensive vision of life; it may be a single idea such as "progress" (in many Victorian works), "order and duty" (in many early Roman works), "seize-the-day" (in many late Roman works), or "jealousy" (in Shakespeare's Othello). The theme may also be a more complicated doctrine, such as Milton's theme in Paradise Lost, "to justify the ways of God to men," or "Socialism is the only sane reaction to the labor abuses in Chicago meat-packing plants" (Upton Sinclair's The Jungle). A theme is the author's way of communicating and sharing ideas, perceptions, and feelings with readers, and it may be directly stated in the book, or it may only be implied. Compare with motif and leit-motif."
From http://web.cn.edu/kwheeler/lit_terms_T.html
Another way of thinking of themes is to ask yourself this: What is the hidden message the author wants you to "get"?