Imagine missing school or work every month because you lacked proper menstrual supplies. How many days per year would you lose in education and wages simply because you got your period? What if no one ever taught you about menstruation, or worse--if menstrual taboos and myths made you feel ashamed of your body?

In 2008, Celeste Mergens was working with an overcrowded orphanage on the outskirts of Nairobi, Kenya, when she learned that menstruating girls sat on cardboard in their rooms for several days each month.

This set into motion a simple idea--combining a washable, long-lasting pad with taboo-breaking education--that became a catalyst for an unlikely global movement for equity.

Written in short, evocative chapters, The Power of Days tells the story of Mergens's quest to rally a global response to elevate menstrual health, increase universal access to menstrual supplies, shatter stigma through education, and advocate for global policy change. Raised in poverty by a mentally ill parent, Mergens learned early on that building the life she wanted would take equal parts determination and humility, traits that led her to create the kinds of inclusive conversations and solutions she is known for around the globe.

The challenges Mergens faced and the lessons she learned, personally and professionally, and the triumphs and resourcefulness of leaders all over the globe are illuminating to all who wish to make a difference and create a more equitable world.

Today, Days for Girls reaches more than 2.6 million women and girls in 145 countries. The organization's impact continues to grow, proving that small changes can create big shifts. This journey to overcome one of the world's most prevalent taboos is proof that no divide is impossible to bridge.