And the Answers are:

1) The Last Battle - from the Chronicles of Narnia;
2) Romeo & Juliet;
3) The Polar Express;
4) The Phantom of the Opera;
5) The Wind in the Willows;
6) Pride and Prejudice;
7) A Christmas Carol;
8) Paul Revere's Ride;
9) O Captain! My Captain!
10) The Giving Tree;
11) The Highwayman;
12) A Tale of Two Cities;
13) A Tale of Two Cities;
14) Hamlet;
15) The Voyage of the Dawn Treader (The Chronicles of Narnia);
16) To Kill a Mockingbird;
17) The Declaration of Independence;
18) The Gettysburg Address;
19) Julius Ceasar;
20) The Hunchback of Notre Dame;
21) Tom Sawyer;
22) The Gift of the Magi;
23) (Shows up in various writings of) Oscar Wilde;