Since 2010 when I finished an early version of my full-length work on Leon Ma. Guerrero, I managed to come up with a number of articles on Guerrero. In the meantime, the plan to publish the biography opened up after having submitted the manuscript for consideration by the Institute of Southeast Asian Studies (ISEAS) (now known as ISEAS – Yusof Ishak Institute) in Singapore and having received a favourable review in 2014. In 2015, Guerrero's family and heirs commemorated his birth centenary at a time when the revision process did not take off. Early in 2016 when I have the luxury of time to fine-tune and rework the manuscript, the outcome is this biography.

As the making of this biography is a journey in itself, I could not have arrived at my destination without the encouragement and help along the way of my family, especially my mom and dad, and relatives, especially Mrs Martha S. Rosa; my former teachers and colleagues, Dr Milagros C. Guerrero, Dr Ma. Bernadette G.L. Abrera, Dr Evelyn A. Miranda, Dr Ferdinand C. Llanes, Dr Bienvenido Lumbera, Dr Ricardo T. Jose, Prof Herman Joseph H. Kraft, Dr Maria Luisa T. Camagay, Dr Filomeno V. Aguilar, Dr Motoe Terami-Wada, Dr Floro C. Quibuyen, Dr Jaime B. Veneracion, Dr Jonathan Chua, Mr Phillip Ramirez, Prof. Elizabeth Siler, late Dr Josefina Cabigon, Dr Laura Lee Junker, Dr Rachel Harrison, Prof Henry David Burton; Mr Alfredo Liongoren and late Mrs Norma Liongoren; Mr Marciano de Borja; Guerrero's immediate family, Margaret Burke Guerrero and David Guerrero; Mrs Carmen Guerrero Nakpil, Mrs Gemma Cruz Araneta; Prof Ajit Singh Rye, late Fr John N. Schumacher, S.J., former Ambassador Juan A. Ona, late Fr. James Reuter, S.J., Mrs Ljiljana Plavsic, Mr Abelardo Caro, Ms Rahilah Yusuf and other helpful staff of the ISEAS – Yusof Ishak Institute.

Along the journey were crucial brief or long stopovers at the National Library of the Philippines, the National Archives of the Philippines in Paco, Manila; University of the Philippines Main Library and its constituent libraries headed at that time by Prof.