If there is more than one author of an article, should you write to both?

The best approach depends on various factors. If the article has a clear lead author or primary contributor, contacting that individual first might be most efficient. If the authors have distinct areas of expertise relevant to your query, contacting them separately could be beneficial. Conversely, if their contributions are highly integrated or you need a collective response, including them on the same email ensures everyone is informed and can collaborate on a reply. Waiting for a response from one author before contacting others can delay your process unnecessarily, especially if the first author is unavailable or unresponsive. Therefore, flexibility in your outreach strategy is key.