The biography published by Doria, with a foreword by Carlos Ruiz Zafón, highlights Agustí's cultural contributions, such as the creation of the literary prize Premio Nadal, which led to the discovery of Carmen Laforet and Ana María Matute, as well as Josep Pla's first book deal.

Doria's book also tries to shed light on details about Agustí's personal life that help readers understand the writer. For example, it reveals that Agustí wrote only in Catalan before the Spanish Civil War, he was a member of the conservative Catalan Regionalist League and he belonged to Royalist circles during Franco's regime and conspired from Switzerland and Madrid against the regime.

Doria also uncovers some personal facts about Agustí that shed light on the characters in his saga. For example, Agustí feared his wife would be unfaithful, which explains the recurring theme of adultery. Other revelations include the fear instilled in him by his father about the harmful nature of revolutions, and the repetitive patterns that can lead to decadence in some families.

As Doria discusses in the biography, Agustí's work is full of details that are related to his own life, such as the idea that the working class always ends up paying for the mistakes of the middle class, something he addressed in the five novels that fall under the nostalgic title La Ceniza Fue Árbol (These Ashes Were Once Trees), which means that "the war had laid waste to everything". Doria uses this idea for the title of the biography Ignacio Agustí, el Árbol y la Ceniza.

The book is being published 100 years after the birth of Ignacio Agustí and 70 years after the publication of his most popular novel, Mariona Rebull, which gave rise to one of the most successful series on the Spanish television broadcaster TVE, La saga de los Rius.

The idea for the biography came about as a result of a news report Doria did in 1993 about the 100th anniversary of the anarchist attack on the Liceu opera house in Barcelona. The journalist's mother said the attack had claimed the life of Mariona Rebull, the main character from La Saga de los Rius, even though she had never actually existed.

The anecdote made Doria think about the importance of La Saga de los Rius for the collective imagination, though the biography of the author did not come out until 2007, when the Castro Foundation expressed an interest in including Ignacio Agustí in its collection and asked the journalist to work on a new release of the five novels Agustí had published. In the process, Doria immersed himself in the life of the novelist, which led to the biography.

Sergi Doria has a PhD in Communication Sciences and is a literary critic for the literary supplement of the Spanish newspaper ABC, as well as a professor at the UIC, the Universitat de Barcelona (UB) and Universitat Ramon Llull (URL). He also published the critical edition of Agustí's complete novels.