Complex sentence: Putnam worked on the translation for twelve years before he published also published a companion volume, "The Portable Cervantes", which included an abridged version of his translation, and has seldom been out of print since its publication nearly sixty years ago.
Split into simpler sentences: Putnam worked on the translation for twelve years before he published it. He also published a companion volume, "The Portable Cervantes", which included an abridged version of his translation, and has seldom been out of print since its publication nearly sixty years ago.