The questions you need answered: Why does Dracula always wear evening dress? Did the Wolf Man have an alcohol problem? And why was the Frankenstein monster's head square?

Saturday is Hallowe'en - the night when all things unholy are said to walk the face of the earth. And they will be making a particular beeline for the cemetery thanks to the invitation of honorary Satanist priest and writer on the occult, Gavin Baddeley.

Vampires, werewolves, re-animated corpses and other assorted ghosts and ghouls will all be putting in an appearance. It all promises to be pretty ... well, hammy is probably the word.

Hammy? Yes, you read that right. Gavin will be revealing the inside secrets of the great Universal horror films of the 1930s and 40s: timeless classics such as Dracula (the 1931 Bela Lugosi version); Frankenstein (same year, with the square-headed monster played by Boris Karloff) and The Wolf Man (the 1941 film with Lon Chaney Jr playing an oddly miserable-looking werewolf). But isn't the problem with these films that, to a modern audience at least, they can seem a bit... naff?

Definitely not hammy: Bride of Frankenstein

Gavin, 48, who lives near York railway station, is having none of it. Maybe a little bit camp, concedes the writer and TV commentator on all things devilish and occult. But naff definitely not.

What we have to remember is that, to audiences of the day, these were truly terrifying films, he says. People were actually known to have fainted from fear while watching them.

He has a great story to tell about one cinema manager who, after a screening of Frankenstein, got a midnight call from a man who had been in the audience.

"He said 'I've just been to see Frankenstein, and I'm so frightened I can't sleep. So I'm going to 'phone you every hour of the night so that you can't sleep either!'"

As for Bela Lugosi's Dracula - he was both terrifying and outrageously sexy to 1930s audiences, Gavin says.

"He was hot stuff - incredibly sexy. A ladykiller in both senses of the word." Lugosi lived the life too, Gavin says: having a very public affair with Clara Bow, one of the celebrated beauties of her day. "She used to go around to Bela Lugosi's house wearing nothing except a fur coat."

Gavin's event, being staged in association with the WEA, will run from 2pm-5pm at the Victorian cemetery. It is being billed as an 'informal interactive afternoon class covering horror cinema between 1914 and 1945'. It will basically take the form of him talking, Gavin says - with copious use of stills from horror films to illustrate the points he's making. There will also be some discussion.

He'll begin with a history of the horror genre pre-1914 - with a look at Victorian melodrama, for example, and the books that Dracula and Frankenstein were based on. There will be some 'behind the scenes' insights - did you know, for example, that some armadilloes put in an appearance in Lugosi's Dracula? "Nobody knows why," Gavin admits.

Gavin Baddeley giving one of his talks

And then Gavin will be asking - and answering - some key questions about those classic 30s films.

Such as?

Well, if you insist, here are just a few...

Why does Dracula always wear evening dress?

There's unquestionably something very stylish about Bela Lugosi's Dracula, with that flowing cape, the white waistcoat, the eyebrows and the immaculately groomed hair that tapers to a point on the forehead. The air of campy menace is added to by the way Hungarian Lugosi speaks English. His English was actually very poor, Gavin says - so he learned all his lines phonetically. "He had no idea what he was actually saying. It gives his Count an other-wordly quality." Lugosi's accent also led to a bit of a spat with Hungary's neighbour Romania, who claimed it was a slur on a national hero to make Dracula sound Hungarian, Gavin says.

As to those clothes the Count wore... He was actually wearing opera dress, Gavin says. The film's makers wanted something that screamed decadent European aristocrat. What better than dressing him as an upper class opera-goer...?

Why did Frankenstein's monster have a square head?

It's a question that many have asked. The answer... it was all to do with trying to make the monster seem in some way realistic: as though he really had been created through the appliance of science, Gavin says. Jack Pierce, the make-up artist who came up with the look for Karloff's monster, apparently went to see a neurosurgeon. "He asked him 'how would you transfer a brain?'" Gavin says. The answer came back: "One way would be to take off the top of his skull, like a lid." So the top of the Frankenstein monster's head does indeed look like a lid...

Did the Wolf Man have an alcohol problem?

There are obvious similarities between werewolves and drunks, Gavin says. "You don't know what you have been up to until you wake up in the morning, wearing nothing but your trousers and covered in mud and blood." But it is true that Lon Chaney Jr, who played the melancholic Wolf Man in the 1941 film of the same name, did indeed have a problem with drink.

His father, the very successful actor Lon Chaney, had never wanted his son to follow him into the profession, Gavin says. The younger Lon insisted on doing so. But, a couple of good parts excepted - as Lennie in 1939's Of Mice And Men and as the Wolf Man - he never had the success his father did. As his career went downhill he hit the bottle harder and harder - although at the time he made The Wolf Man he was still at the stage of being a social drinker, Gavin says.

• Nightmares in Black and White: A Celebration of the Golden Age of Hollywood Gothic is in the Chapel of Rest at York Cemetery from 2-5pm on Saturday October 31. Tickets £12. Book via the event's Facebook page (type the event name in Google and it will take you there) or by emailing gavinbaddeley@rocketmail.com