No one who is even passingly familiar with the history of the Chicago Police Department can claim to be surprised by a new report showing that the department is plagued by systemic racism and operates with utter disregard for the lives of the black citizens whom it batters, maims and kills.

Nevertheless, this report, issued on Wednesday by a task force appointed by Mayor Rahm Emanuel, lays out with extraordinary clarity the department’s long record of racial profiling, torture and killings and makes scores of recommendations that might offer Chicagoans some hope.

Mayor Emanuel created the task force in December, not long after the city released a police video showing a white police officer, Jason Van Dyke, executing a black teenager named Laquan McDonald on a street on the South Side of Chicago. The video contradicted a police news release saying that the young man was killed because he had been menacing the officer. Officer Van Dyke was not charged with murder until November, more than a year after the killing. There is no reason to believe that the officer would ever have been charged had a judge not ordered the city to make the video public.

The city’s decision to withhold the video for 13 months — even as the police presented false accounts of what had happened — tapped into long-simmering rage about the injuries and deaths of other African-Americans at the hands of the police. The brutality dates back decades and includes episodes like the Police Department’s execution of the Black Panther leader Fred Hampton during a raid in 1969 and the infamous “midnight crew’’ that beat and tortured black men from the 1970s to the 1990s. Besides killings, the department also has a long history of false arrests, coerced confessions and wrongful convictions.