The naming of the txt files is of mixed to good usefulness for you. First ten listed as example.

    - 0/0.4 - Mike Lancaster.epub.txt
    - 0/0.721 - Gary Webster.epub.txt
    - 0/01 - Alec Dunn.epub.txt
    - 0/01 Kai_ Ninja Of Fire (Scholastic) - Greg Farshtey (retail).epub.txt
    - 0/02 Crescendo -  Becca Fitzpatrick.epub.txt
    - 0/03 Cole_ Ninja Of Earth (Scholastic) - Greg Farshtey (retail).epub.txt
    - 0/03 - Jean-Christophe Valtat.epub.txt
    - 0/04. R. W. Peake - Antony and Cleopatra Part I Antony (Marching With Caesar, Book 4) [Retail].epub.txt
    - 0/05. R. W. Peake - Antony and Cleopatra Part II Cleopatra (Marching With Caesar, Book 5) [Retail].epub.txt
    - 0/05 LEGO Ninjago - Snake Attack! (Scholastic) - Tracey West (retail).epub.txt

Apologies, I had included the wrong corpus originally, the correct list is this one.

Second edit - Books3 is much cleaner than Books1, I am editing my negative opinion to a more positive one to reflect that.