Lillie Green and her son exchanged dozens of letters after he entered the Army in 1917. In the summer of 1918, several of the envelopes she had addressed to Pvt. Jasper Green came back to Greenleaf, Idaho, with a heartbreaking word stamped in red.Deceased.The 24-year-old soldier had been gravely wounded on July 22, 1918, in one of the pivotal battles of World War I. Jasper died a month later, even as Lillie and other family members continued to send him letters.“They were writing to him, and they didn’t know he was gone,” said Diane Green-Hartley, Lillie’s great-granddaughter.That was not the end of Lillie’s writings, however. In 1930, she became one of 6,654 American mothers and widows who visited the graves of their sons and husbands in Europe.Lillie Green kept a diary during her journey, describing where she and her fellow Gold Star women went and what they saw.The diary and the WWI letters — almost 100 years old — plus other family keepsakes help tell a little-known chapter of American history. Green-Hartley wove them into an account of her great-grandmother called “Lillie’s Jasper: The 1930 Pilgrimage of a Gold Star Mother.”Keeping her story aliveThe book started out as an exercise in preserving the diary of Lillie’s trip.“My parents knew about its existence, and they knew it was a good story, and they asked me to type it,” the author said recently in her Hazel Dell home.