Cornelis de Witt Willcox 
Head Hunters of Northern Luzon [PDF ebook] 
From Ifugao to Kalinga, a Ride Through the Mountains of Northern Luzon; With an Appendix on the Independence of the Philippines

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. In 1910 the Secretary of the Interior of the Philippine Islands did me the honor to invite me to accompany him on his annual tour of inspection through the Mountain Province of Northern Luzon. In the following pages I have tried to describe what fell under my notice during the journey, with such comments, observations, and conclusions as seemed pertinent.