Like the previous story Logopolis, Castrovalva is a complex, imaginative and thought-provoking story with some very interesting concepts but is probably not the most accessible story for casual viewers/listeners. I adore Christopher H Bidmead's writing style, it often goes off on little tangents but it has the effect of making the story more absorbing and memorable and he has a great way with words, and an impressive vocabulary and clearly a good scientific knowledge. The first half of the story is very self-contained, concentrating soley on the Doctor and his companions in the TARDIS and the effects of the Doctor's regeneration and while short on incident it benefits from giving a good insight into the characters and to exploring the interior of the TARDIS better than has ever been done before or since. The second half picks up the pace with the arrival in Castrovalva and the complex trap that has been set for the Doctor. The way Bidmead describes the town of Castrovalva and the slow realization that all is not as it seems is very cleverly done and hugely satisfying. The fifth Doctor himself, Peter Davison, reads this story and does an exellent job of it. His voice is quite similar to Bidmead's, which makes this fit well with the previous audio of Logopolis which was read by Bidmead. Davison does the various characters well, especially the Master and although his voice now sounds a little older than when he was the Doctor he still has the character to a tee. In short, Castrocvalva, along with Logopolis are, for my money, the two best Doctor Who novelizations ever written and these audios are also probably the best in the range so far. An essential purchase.