Published in 1911, El árbol de la ciencia is considered by Pío Baroja himself as "the most complete and accomplished book of all my works." This novel showcases the novelist's narrative technique at its most effective, characterized by the uninterrupted succession of events, the abundance of secondary characters, the skillful articulation of critical situations, descriptive impressionism, and the rapid sketch of characters.

Azorín noted that this book best captures the spirit of Baroja, blending his philosophical and social principles with autobiographical elements. The protagonist, a doctor like Baroja, witnesses the injustices of a petty and degraded society, caught between physiological determinism and moral rebellion, searching for his own path.

This semi-autobiographical work spans the years 1887 to 1898, offering a privileged insight into the author's world.