Rare autograph by Janis Joplin, signed at the famous 1970 birthday party of her mentor Kenneth Threadgill. Joplin signs the back of an envelope, ''Bruce & Matt / Love from yr Dad & / Janis Joplin [heart symbol]''. Autograph was obtained by Texas Representative Neil Caldwell for his sons on an envelope of Texas Congressman J.J. Pickle, who also attended the famous 10 July 1970 party. Joplin would pass away less than three months later. Penned in blue ballpoint, envelope measures 3.875'' x 8.875''. A few pinholes, toning and folds, overall very good condition. With Roger Epperson COA.