Invented in the 18th century to withstand the rigours of physical labour, overalls were originally called “slops.” Workers embraced them en masse, and wore them in standardized colours that signified their particular trade. This season, overalls have been retooled for high fashion by designers such as Philip Lim and Margaret Howell. Utilitarian? Quite, if your job is to look unexpected and fetching. Here's how to pull off overalls now.