This is Black Widow - Clarissa S Wong

The Marvel Heroes of Reading line of early readers is designed to offer reluctant readers, specifically boys, books that they will want to read by featuring characters they love. The series is broken into three levels that invoke the rigorous training courses their favorite Marvel heroes must engage in to perfect their super powers. In reading this series, boys will prefect their own power to read.

This is Black Widow introduces readers to Natasha, an Avenger and one of S.H.I.E.L.D.'s top secret agents, and how she became known as Black Widow.