The author has witnessed a few ghosts of his own and his experiences are included in "Ghosts and Hauntings", along with hundreds of other eye-witness accounts that he solicited through newspaper and radio ads (primarily in Great Britain). This book was originally published in 1965, and several of the stories are of pre-war and World War II vintage. Bardens also includes several often-published stories such as the ghostly bear in the Tower of London, Lord Soulis and his pact with the Devil, and the haunting of Borley Rectory. He tries to stick to accounts that had two or more witnesses who were willing to corroborate each other. For some of his chosen hauntings, there were a hundred or more witnesses, and for others, the story was too good to omit even if only one person had seen or heard the ghost.
Haunted ships are well represented in "Ghosts and Hauntings", although Bardens' 'Flying Dutchman' doesn't resemble the 'Flying Dutchman' I'd heard about from other sources (What plague? What pirates?). If you were frightened by that horrid little ghost story, "The Upper Berth", then this book's seafaring ghosts will really raise the hair on the back of your neck. I swear I'll never go on another cruise!
One minor problem I had with "Ghosts and Hauntings" was that the author kept interjecting his theories on the origins of supernatural phenomena into the stories. I think his writing would have been even more eerie and interesting if he had simply reported the hauntings, and kept his theories of cerebral electricity for another publication.
Definitely read Barden's book if you enjoy excursions into the realm of true hauntings. Just go quickly over the parts about electricity in the brain.