Alright, I emailed Miranda. I think the book MIGHT be that book Romeo was reading in his first echo. Here's a transcript of the first email:
My email:
Hello, Miranda. I found your website while looking through random rare book sites. I have several of them, as I'm a collector of sorts. I'm sorry to hear that you guys sold your shop, because I was wondering if you had a specific book I'm missing from my collection. It's called "Off the Top of My Head". I don't know the name of the author, unfortunately.
Thank you.
Her response:
Hello!
Let me check my records for you. If we had it, I should have its current location in my records. If you can figure out the author, it might make my search go a little quicker. Everything is logged by the author. If not, I'll go as quickly as I can!
Miranda Auspice
Flamingo Rare Books
flamingorarebooks.wordpress.com
So, I think I might be on the right track.

Edit: I'm going to email her back and give her a description of the cover of the book. It might not help in the slightest, but it's worth the shot.
Edit2: Alright, I emailed her back, and I'm awaiting a response. Here's what I sent:
Hey, Miranda. Unfortunately, I couldn't find the name of the author. A google search of the title turned up nothing except for a few forums with a few pictures; however, they were too blurry for me to make out the author's name. I was, however, able to see the cover of the book. It shows a man in grayscale dressed in a suit and tie, but with the top half of his face cut off. This probably won't help you, but it's all I've got, unfortunately.
Edit3:
Her reply:
There are a couple of options. The cover, if it is a photograph, could be a picture of the author. That is more common in nonfiction books, particularly autobiographies. It could be a picture of the main focus of the book, which is common if it is a biography. It could also be a picture of the main character.
If any of these suggestions help you with identifying more about the book, let me know!
Miranda Auspice
Flamingo Rare Books
flamingorarebooks.wordpress.com