Many years ago, when I was a very poor Ph.D. student, I spent a term working at the Angus Library, Regent’s Park College, Oxford. With very limited resources, I purchased several out-of-print journals and books, but I had to decline what would have been a true prize, a complete set of the Transactions of the Baptist Historical Society. This was the early name for what would become The Baptist Quarterly, and was published in seven volumes from 1908-1921. It is full of incredibly valuable material, including many reprinted primary sources from the Seventeenth century.
All of this material has been in the public domain for a few years now, and has been made available for free here. Additionally, the entire set may be downloaded in .pdf format. This is a great bounty. And beyond this wonderful resource, the early issues of The Baptist Quarterly are also being scanned and placed on the same website.