In a special one-off return for a chat podcast, Doctor Who cosplayer Brian A. Terranova tells Christian Cawley about the research into his remarkable history of the RTD era sonic screwdriver, available to download as a free PDF.

We can't possibly discuss everything about the PDF in this little box of text, but suffice to say Brian has been researching the device for over a decade, collecting replicas, analyzing photos and screen caps, and learning as much as possible about it.

The end result is the PDF download, free to anyone, which we discuss in our latest podcast.