I enjoyed this one so much that rather than reach back into the dark abyss of the bazillion unread Kindle books I already own, I bought and have already started the next book in this series.
Overall this is very, very good. An adventure in 1920's Paris, seeking to obtain and copy a never published novel by a (fictitious) famous author, trying not to be outted as time travelers from the future, there's a bit of a sweet romance but it's not angst ridden and is just one thread in a complex plot. There's also a mysterious serial killer on the loose. A serial killer that was not recorded in history. In addition to all that, Stassi is seeking information to help her find out about her unknown birth parents due to a clue from that time and place.
The MC, Stassi, and her partner tease each other like brother and sister, obviously care for each other (non-romantically) and are loyal. I enjoyed their relationship, as well as Stassi's relationship with her best friend, Molly. The characters all have their own personalities and truly feel like individuals.
There's humor here, and a lot of heart. As well as mysteries and adventure.
I've noticed a couple minor editing errors, but no more than you might find in a traditionally published novel. One continuity error, but it was something extremely minor and unimportant. I also noticed a couple small anachronisms. A couple characters in 1920's Paris call the protagonist "Ms.", rather than "Miss". Another character tells a funny story about a woman who spent an evening with the back of her dress stuck in her hose - which only happens with pantyhose, which were not yet invented. So, not perfect, but relatively minor issues.
A few logically questionable issues, due to playing around with time. I think those could have been explained so they made sense a bit better, but nothing worthy of real complaint. One thing I truly did question as something that seems like it would effect history, that wasn't explained to my satisfaction. It would be spoilery to be more specific. It happened at the end, so I'm also thinking it may be addressed in book 2.
Overall, I really enjoyed it. The story is engaging and interesting, the writing is good, and I like the characters.