One of the book's strengths is its exploration of Feeney's philosophy of "Giving While Living." Unlike many billionaires who accumulate wealth throughout their lives, Feeney was committed to using his resources to make a difference during his lifetime. He chose to donate his fortune to various causes and initiatives, often with a focus on education, healthcare, and research.

O'Clery delves into the intricacies of Feeney's philanthropic activities, including his founding of the Atlantic Philanthropies, a secretive organization that made transformative donations to universities, hospitals, and other institutions. Feeney's approach to philanthropy, marked by humility and a desire for impact, stands out as a unique and inspiring aspect of his life.

The book also explores the challenges and controversies surrounding Feeney's philanthropic efforts, including legal battles and issues related to maintaining the secrecy of his donations. These challenges add depth to the narrative and highlight the complexities of large-scale philanthropy.

While "The Billionaire Who Wasn't" provides a compelling account of Feeney's life and philanthropy, some readers may find that the book's level of detail and focus on financial transactions can be overwhelming at times. Additionally, it may not offer as much personal insight into Feeney's motivations and inner life as some biographies do.

In conclusion, "The Billionaire Who Wasn't: How Chuck Feeney Secretly Made and Gave Away a Fortune" is a thought-provoking biography that sheds light on the extraordinary journey of a billionaire who chose to use his wealth for the greater good. Chuck Feeney's story serves as an inspiration for those interested in philanthropy and the potential for personal wealth to create positive societal impact. Conor O'Clery's meticulous research and storytelling make this book a recommended read for those seeking a deeper understanding of Chuck Feeney's philanthropic legacy.