If a single author substantially writes the book, it is copyrighted in that author's name. A group-effort book is usually copyrighted in Chaosium's name. Authors get 6-12 free copies, more if they need them, and can always get additional copies at standard discounts. Payment may be segmented. For instance, there might be a modest advance upon acceptance of the manuscript, and the remainder of the payment thirty days after publication, or as otherwise agreed.
Arrangements vary by author.
Chaosium reserves the right to revise, correct, expand, or condense material using the Call of Cthulhu game system. The Common Pool Just as Mythos authors have done since the original Lovecraft Circle, we ask that new authors allow other authors to refer to or employ the characters, tomes, entities, and spells that they create. In exchange, such elements within the rulesbook and supplements are available for your use. If they wish, authors maintain complete control of their own human characters, and may always use them in other publications and other media. The substance of these points varies by book, topic, and author.