In Without a Margin for Error, the author chronicles the journeys of young adults in an under-served urban community who are new to the English language into STEM (science, technology, engineering, and mathematics-related) fields from high school through college. He distills lessons, themes, and policy recommendations from the trails blazed by these students toward altering the status quo around college access and STEM success for often-marginalized but highly resilient young adults with much to contribute to their new nation, their communities, and the world. While drawing on a critical ethnography of over three dozen inspiring young adults, seven students are chronicled in greater depth to bring to life crucial conversations for redefining college readiness, access, and success in STEM fields.