Four decades ago, Robert A. Caro began writing a multipart biography he calls The Years of Lyndon Johnson. Over 3,000 pages and a Pulitzer later, he’s still working on the fifth and (allegedly) final volume. 

“In writing about me and my hopes of finishing, [journalists] often express their doubts of that happening in a sarcastic phrase: ‘Do the math,’ ” Caro, 83, writes in the introduction to Working, a new book about his research. 

Yet concern over longevity might be better suited to his tools. Caro writes first drafts longhand, then types them up, complete with carbon copies, on a Smith-Corona Electra 210 typewriter. He spoke to Popular Mechanics about the equipment that has facilitated some of the best historical writing of our time, or any time.