Seated in her eight-room apartment, in a wealthy section of Hong Kong, Kathryn Louey stared quietly at her copy of Xyza Bacani’s first book, “We Are Like Air,” studying the words and photographs carefully. When she finished, she sought out Xyza’s mother, Georgia, who was in another room of the apartment they share, and the two hugged and cried together.

These were not just tears of joy.

This book is largely about Georgia’s life story — as a Filipino domestic worker trafficked and mistreated in Singapore for two years before she ran away and found a safe haven with Ms. Louey, her kind and generous employer in Hong Kong, for the past 20 years.

It is also the story of Xyza, who at 8 years old was left behind to raise her younger siblings in a rural town in Nueva Vizcaya Province in the Philippines; a decade later, she followed in her mother’s footsteps and became a domestic worker in Ms. Louey’s home for nine years. The book also recounts Xyza’s unlikely journey from migrant domestic worker to street photographer to social documentarian telling the stories of migrant workers in Singapore, many of whom were abused, trafficked and swindled, as well as those in Hong Kong and New York.