Library staff undergo A.R.P. (Air Raid Precautions) training on the Central Library's roof during the second world war. The building's basement was used as an air raid shelter, and many of its staff went on "fire watch" on the roof. The library itself wasn't bombed, but the aftershock of a nearby bomb made a crack in its marble floor which can still be seen in the foyer today.
For more information, see Sheffield At War: A Pictorial Account 1939-45, published by The Star.
Image used with permission from Sheffield Local Studies Library, www.picturesheffield.com.