Writing a series about decisions made a century or more ago presents a challenge, as everyone involved is long dead. But when the subject is a company with the pride of Sherwin-Williams, historical documents abound. The Cleveland paint company produced histories about itself at regular intervals and preserved internal magazines for employees from the late 1800s on. Our Sherwin-Williams Dilemma is based partly on those records, along with government transcripts, books, magazines, newspapers and court records. Many of the documents have been assembled by Columbia University and the City University of New York on their website, toxicdocs.org, which hosts millions of pages of once-secret corporate documents about asbestos, polyvinyl chloride, benzene, silica and, of course, lead.