Answer:
Ms. Librarian,
You may not know me, but I am a frequent in the library. I love to read and I'm looking for a copy of (book title) but realized you don't have a copy. Is there a way you can procure a copy for me? If so, please let me know. It's real important that I get this book as it's my favorite book from my childhood.
Sincerely,
(Your Name)
Step-by-step explanation: