David Lagercrantz is a Swedish author and journalist, best known for continuing the popular Millennium series originally created by Stieg Larsson. He took over the series with the novel "The Girl in the Spider's Web," which was published in 2015 and became a bestseller. Lagercrantz has also written several other books, including biographies and novels. His writing often explores themes of technology, society, and human relationships, showcasing his ability to blend thrilling narratives with deep character development.