After looking at all the title options, this one stands out as the clear winner for search optimization.
The biggest reason this title works so well is that it immediately tells people what they're looking for. Most people searching "Jessica Blackwood" want to know about the fictional FBI agent from Andrew Mayne's thriller novels, not the real person who works in accessibility at McMaster University.
What makes this title particularly effective is the phrase "solves impossible cases." This creates that irresistible urge to click because people naturally want to know what makes these cases impossible and how she manages to solve them. It's the kind of hook that makes you stop scrolling and actually click through to read more.

The word "Books" right at the beginning is crucial too. It instantly clarifies that we're talking about the literary character, which saves people time and matches exactly what they're searching for. Nobody has to wonder if they're going to read about the wrong Jessica Blackwood.
At characters, the title fits perfectly within Google's display limits without getting cut off. This means the full impact of the title shows up in search results, giving it the best chance to grab attention.
The FBI agent angle works because it establishes credibility and sets clear expectations about the genre. Thriller and mystery readers immediately understand what kind of content they'll find, which leads to better engagement once they click through.
This title succeeds because it answers the searcher's question while creating enough intrigue to make them want to learn more. It's straightforward enough to be trustworthy but compelling enough to drive clicks.