Reading order
| # | Title | Published | Author | Buy on Amazon |
|---|---|---|---|---|
| 1 | Unwrapping the Castelli Secret | 2015 | Susan Stephens | Buy |
| 2 | Brunetti’s Secret Son (Secret Heirs of Billionaires) / Christmas at the Chatsfield | 2015 | Susan Stephens | N/A |
| 3 | Brunetti’s Secret Son/ Christmas at the Chatsfield | 2015 | Susan Stephens | Buy |
| 4 | The Secret to Marrying Marchesi | 2016 | Susan Stephens | Buy |
| 5 | Demetriou Demands His Child | 2016 | Susan Stephens | Buy |
| 6 | The Desert King’s Secret Heir | 2016 | Susan Stephens | Buy |
| 7 | The Sheikh’s Secret Son | 2017 | Susan Stephens | Buy |
| 8 | The Innocent’s Shameful Secret | 2017 | Susan Stephens | Buy |
| 9 | The Greek’s Pleasurable Revenge | 2017 | Susan Stephens | Buy |
| 10 | The Secret Kept from the Greek | 2017 | Susan Stephens | Buy |
| 11 | Carrying the Spaniard’s Child | 2017 | Susan Stephens | Buy |
| 12 | Kidnapped for the Tycoon’s Baby | 2017 | Susan Stephens | Buy |
| 13 | The Greek’s Secret Son | 2018 | Susan Stephens | Buy |
| 14 | Claiming His Hidden Heir | 2018 | Susan Stephens | Buy |
| 15 | The Secret the Italian Claims | 2018 | Susan Stephens | Buy |
| 16 | Demanding His Hidden Heir | 2018 | Susan Stephens | Buy |
| 17 | The Heir the Prince Secures | 2018 | Susan Stephens | Buy |
| 18 | The Italian’s Unexpected Love-Child | 2018 | Susan Stephens | Buy |
| 19 | Wed for His Secret Heir | 2018 | Susan Stephens | Buy |
| 20 | The Baby the Billionaire Demands | 2018 | Susan Stephens | Buy |
| 21 | Married for His One-Night Heir | 2018 | Susan Stephens | Buy |
| 22 | The Secret Kept from the Italian | 2018 | Susan Stephens | Buy |
| 23 | Demanding His Secret Son | 2019 | Susan Stephens | Buy |
| 24 | Sicilian’s Secret Son | 2019 | Susan Stephens | N/A |
| 25 | The Sheikh’s Secret Baby | 2019 | Susan Stephens | Buy |
| 26 | Claimed for the Sheikh’s Shock Son | 2019 | Susan Stephens | Buy |
| 27 | The Sicilian’s Secret Son | 2019 | Susan Stephens | Buy |
| 28 | Shock Heir for the King | 2019 | Susan Stephens | Buy |
| 29 | The Maid’s Spanish Secret | 2019 | Susan Stephens | Buy |
| 30 | Sheikh’s Royal Baby Revelation | 2019 | Susan Stephens | Buy |
| 31 | Cinderella’s Scandalous Secret | 2019 | Susan Stephens | Buy |
| 32 | Unwrapping the Innocent’s Secret | 2019 | Susan Stephens | Buy |
| 33 | Proof of Their One-Night Passion | 2019 | Susan Stephens | Buy |
| 34 | The Italian’s Unexpected Baby | 2019 | Susan Stephens | Buy |
The Secret Heirs of Billionaires series is one of Harlequin Presents’ largest themed collections, with 34 books published between 2015 and 2019. Every story follows the same core premise: a wealthy hero discovers he has a child he never knew about. How that revelation plays out varies from book to book, but the emotional beats are consistent. The hero wants to claim his heir, the heroine has her reasons for keeping the secret, and the resulting tension drives both the conflict and the romance.
The settings range widely. The Desert King’s Secret Heir and Sheikh’s Royal Baby Revelation go to the Middle East, while The Secret the Italian Claims and The Sicilian’s Secret Son stay in the Mediterranean. Titles like Carrying the Spaniard’s Child and The Maid’s Spanish Secret bring the action to Spain, and Claiming His Hidden Heir keeps things in the British upper class. Multiple authors contributed to the banner, so writing styles differ, but the unifying theme holds the collection together.
At 34 books, this is a series for readers who love the secret baby trope and want enough variation to keep it interesting across dozens of entries. The four-year publication window means you get a steady stream of new couples and settings without the concept wearing thin.