It's time for a new series of The Library of Impossible Things.

In this episode, Si is delighted to be joined by author and friend, David K. Barnes.

What object will David bring into The Library? Who were the two Doctor Who fans he met first? What was it like to write for his hero? And what or who was The Secretive Bus?

Take another trip into The Library of Impossible Things to find out the answers to these questions and so much more!