CHENEY – The period of time between World War I and World War II was one of change – cars were slowly taking over where horses and buggies used to be, telephones were becoming more and more common, and the roles of women were changing, too. It’s a time Ernestine McMillan Hilton, 88, chronicles in a memoir of her childhood, growing up just to the west of where Cheney is today. Her book, “Once Upon a Green Meadow: An American Family’s Struggles Between the Wars,” will be the topic of conversation at the Cheney Community Library on Tuesday.