Barbara Gregorich's baseball writing started with the well-received novel She's on First. This story of the first female major leaguer was praised by Publishers Weekly, which wrote that "all baseball fans will appreciate Gregorich's sure feel for the game . the baseball scenes are crackerjack, and readers should end up wondering, 'Why not?'"After writing the fictional version of women in baseball, Gregorich began the long job of researching the true story of women who played hardball. The result of that research was Women at Play: The Story of Women in Baseball, published by Harcourt, 1993. Women at Play won the SABR-Macmillan Award for Best Baseball Research of the Year. In 2013 Women at Play was included in Ron Kaplan's 501 Baseball Books Fans Must Read before They Die. The work that went into researching women who played baseball (from 1875 onward) was intense, and the accumulated articles filled several file boxes. In 2010 Gregorich published Research Notes for Women at Play: The Story of Women in Baseball, Volume I, offering the most important of the newspaper articles she had found - some in their entirety and some in summary.

Volume II followed in 2013 and Volume III in 2015, concluding the Research Notes series.In addition to writing about baseball, Gregorich has written the mystery novels Dirty Proof and Sound Proof. She has also written the well-received Guide to Writing the Mystery Novel: Lots of Examples, Plus Dead Bodies.Gregorich studied at Kent State University, the University of Wisconsin, and Harvard. She worked as an English instructor, a typesetter and a letter carrier. She lives in Chicago with her husband, Phil Passen.