( CNN ) -- During the past six seasons of the television show `` Mad Men , '' audiences and fashion designers alike have obsessed over the cast 's retro wardrobe . So has Linda Przybyszewski , a University of Notre Dame history professor and the author of the upcoming book , `` The Lost Art of Dress : The Women Who Once Made America Stylish . '' The 1960s , the decade that `` Mad Men '' has inhabited thus far , was a time of tremendous upheaval that challenged the principles of the past -- and the fashions , she said . As women and African-Americans fought for social equality and men struggled to normalize their home and work lives , everyone 's clothing changed . What the late '60s really looked like . We asked Przybyszewski to weigh in on how the `` Mad Men '' wardrobe evolved , and clue us in to what those shifts said about the time . Fans do n't yet know in what years the show 's final season will take place , but count on some bold , colorful changes . After all , at the start there were `` four guys essentially wearing identical suits , and now we have four guys each one of them with distinctive facial hair , color , cut , garment , '' she said . `` That 's what the '60s did . ''
The wardrobe of `` Mad Men '' has changed dramatically over six seasons . The social upheaval of the 1960s played out in the clothes people wore . Linda Przybyszewski 's book , `` The Lost Art of Dress '' comes out in May .