The book reviews of the early Philosophical Transactions have not been considered a dominant feature of the journal, and thus more research is needed to enrich our understanding of them. This paper begins this process by describing some of the basic features of the reviews, before moving on to address the issue of how they were composed. The specific focus here is on how Henry Oldenburg’s correspondence influenced the process in various ways. As it turns out, there are episodes when (...) Oldenburg’s exchanges impacted the timing, length, content, form, and sometimes even the very existence of the book reviews. It thus seems that these reviews were rooted just as much in epistolary correspondence as other texts published in the Transactions. (shrink)