The Recommended Reading Path
For readers diving into the CSI Reilly Steel series, there are two primary routes to explore. Because the series centers heavily on the personal evolution, family trauma, and professional struggles of protagonist Reilly Steel, reading the books in order is highly recommended to appreciate her character arc. However, you have a choice in where to begin.
Option 1: Publication Order (Recommended)
Starting with the debut novel, Serial (originally published as Taboo), is the path most fans recommend. This introduction throws you straight into Dublin's forensic world, matching the reader's discovery of the setting with Reilly's own adjustment to her new Irish surroundings. You get to experience the mystery of her past unfolding gradually, just as the authors originally intended.
Option 2: Chronological Order
If you prefer to understand a protagonist's origin story before seeing them in action, you can start with the prequel novella, Crime Scene (also published as Quantico). This short book is set during Reilly's training days in the United States and sets up the behavioral analysis and forensic foundation she uses throughout the main series. After the prequel, you proceed directly to book one.
CSI Reilly Steel Books in Order
Due to different publishers and regional releases in the US, UK, and Ireland, almost every book in this series has been published under two or even three different names. The list below provides the correct sequential order of the novels alongside their alternative titles to help you avoid accidentally buying the same book twice.
- Book 0.5: Crime Scene / Quantico (2014)
Note: A prequel novella detailing Reilly’s FBI training at Quantico before her move to Ireland. - Book 1: Serial / Taboo (2011)
Note: The official start to the series. Reilly joins the Dublin Garda Forensic Unit and tracks a serial killer with a bizarre moral agenda. - Book 2: Victim / Inferno / Torn (2012)
Note: A killer begins staging crime scenes inspired by Dante's Divine Comedy, forcing Reilly to decode literary clues. - Book 3: Hidden / The Perfect Life (2013)
Note: Dublin is rocked by a series of murders involving victims marked with mysterious tattoos linked to ancient Irish myths. - Book 4: The Watched (2014)
Note: Reilly finds herself dealing with a voyeuristic stalker whose crimes escalate into deadly violence. - Book 5: Trace / One Little Mistake (2014)
Note: The investigation turns to a gourmet-obsessed killer with highly specific, unsettling motives. - Book 6: Aftermath / Pretty Guilty Secrets (2015)
Note: Reilly and her team deal with the fallout of past cases while tackling a fresh, deeply personal investigation. - Book 7: Endgame / The Perfect Lie (2017)
Note: High-stakes psychological games push Reilly and the Dublin forensic team to their absolute limits. - Book 8: Last Girl Alive / Fallout (2022)
Note: Reilly returns to face a chilling case that tests her forensic expertise and survival instincts. - Book 9: The Profiler (2026)
Note: The latest installment shifts focus to Reilly's former mentor, Daniel Forrest, in Florida, as he works a high-stakes beachfront hostage case.
What to Know Before You Start
Casey Hill is actually the collective pen name of the bestselling Irish husband-and-wife writing team Melissa Hill and Kevin Hill. Melissa Hill was already widely known for her successful contemporary women's fiction and romance novels (such as Something from Tiffany's) before she decided to partner with her husband Kevin to write dark, forensic-focused thrillers. The pen name "Casey" was created as a nod to their daughter, Carrie.
By combining Melissa's talent for deep character development and suspense with Kevin's practical, grounded perspective, the duo created a series that reads like a cross between CSI: Crime Scene Investigation and classic psychological thrillers. The books are heavily set in Dublin, Ireland, offering a unique regional spin on the forensic genre, highlighting the operations of the Garda Forensic Unit (GFU).
Chronological Order and Alternate Title Caveats
The sheer number of alternate titles in the CSI Reilly Steel series is the single biggest point of confusion for readers. The books were released with different titles to appeal to US and UK audiences respectively. When purchasing or borrowing the novels, always double-check the publication year and the alternative titles listed above to ensure you are selecting the correct next step in the series.
In terms of chronology, the prequel Crime Scene / Quantico was actually written and published after the series was well underway. While it acts as Book 0.5, it contains minor nods to Reilly's future that are fun to catch if read as a flashback later, though starting with it does not spoil any major plot points of the main novels.
Are the Books Standalones?
While the central mystery or serial killer investigation in each book is self-contained and resolved by the final page, the overarching character relationships, romance subplots, and Reilly Steel's personal trauma build continuously from one book to the next. Reading them out of order will spoil major developments regarding Reilly's family history and her relationship with her colleagues in the Garda Forensic Unit. For the best reading experience, stick to the numerical sequence.