For the article on the book, see.
Victorian Age: Vampire is a setting for Vampire: The Masquerade that many felt was an obvious choice: the Gothic Victorian period. The Victorian era gave birth to many of the modern tropes that the World of Darkness draws from (gentlemen vampires, man-made monsters, ghosts, faeries), so it was a natural choice.
It was hoped by many that Victorian Age: Vampire would be successful enough to spawn its own series, much like the Dark Ages line had with Dark Ages: Werewolf, Dark Ages: Mage and so forth. Unfortunately, only three VA:V books were produced (and a trilogy of novels) before the World of Darkness ended. Werewolf: The Wild West however takes place in a similar time, so even if it takes place on another continent it can be used supplementally.
While the Victorian Era is generally considered to last the duration of the reign of Queen Victoria, the Gothic Victorian is specified as spanning the time from 1880 (the founding of the Hermetic Order of the Golden Dawn) to 1897 (the publication of Bram Stoker's Dracula, after which public perception of vampires changed).
The books focus mainly on historical facts and its influence on Kindred society. The sects do exist, but even though the Camarilla is very strong in that time they are not as relevant as in Vampire: The Masquerade. Gehenna also doesn't feel as close. The books also focus on London which was the center of the British Empire. Secret societies and the high society's interest in occultism dominate the era. The contrast between rich and poor is very strong and the streets are full of homeless. The books about Sherlock Holmes take place during this time; Jack the Ripper rages in 1888 and people start thinking about the ideas of Marx and Freud.