Give Washington Post reporter Leon Dash credit for his series on Rosa Lee Cunningham and her family; the Pulitzer committee did. If nothing else, Dash managed to take off the safari helmet of daily journalism and tell a true story about the desolate terrain inhabited by Cunningham, a Washingtonian since childhood. It was inevitable that Dash would leverage the exalted eight-part Post series about a drug-addicted grandmother into a book, but it wasn’t necessary. The infill is transparent and for the most part not additive. Rosa Lee: A Mother and Her Family in Urban America has the same strengths as the series and its subject: a refusal to flinch in the face of unbelievable abasement. But at book length, Dash’s ability to show far outstrips his ability to tell. Dash reads and signs at 7 p.m. at Joe’s Movement Emporium, 3802 34th St., Mount Rainier. FREE. (301) 699-1819. (David Carr)