The Bobbsey Twins

A long running series ghostwriten under the pen name of Laura Lee Hope by the Stratemeyer Syndicate which follows the Bobbsey Family, composed of two sets of fraternal twins and their parents. Bert and Nan are the older dark-haired set of twins and Freddie and Flossie are the younger blonde twins. When the first book was written and set in 1903, Bert and Nan were eight years old and Freddie and Flossie four. Seventy-two volumes later, the last book was written and set in 1979 with Bert and Nan having aged to 12 and Freddie and Flossie aged to 6.

Primary characters:

Mr. Richard Bobbsey - owner of a lumber yard in Lakeport.
Mrs. Mary Bobbsey - his wife.
Nan Bobbsey - their elder daughter, Bert's twin.
Bert Bobbsey - their elder son, Nan's twin.
Freddie Bobbsey - their younger son, Flossie's twin.
Flossie Bobbsey - their younger daughter, Freddie's twin.

Secondary characters:

Dinah Johnson - the Bobbseys' black cook, Sam's wife.
Sam Johnson - the Bobbseys' man of all work, Dinah's husband.
Snoop - the Bobbseys' cat, originally a stray kitten befriended and adopted by Freddie.
Snap - the Bobbseys' first and oldest dog, a retired circus dog.
Waggo - The Bobbseys' second dog, a highly energetic foxterrier.
Danny Rugg - a "bad boy."

The following tropes are common to many or all entries in the The Bobbsey Twins franchise.
For tropes specific to individual installments, visit their respective work pages.

Adaptation Displacement: Starting in 1960, the Syndicate began introducing new editions of the old books to update the technology and remove some of the Values Dissonance inherent to starting at the turn of the century. In some cases, entire storylines were changed.
Ambiguous Gender: Snoop the cat. One of the more curious parts of the Continuity Drift/Continuity Snarl mentioned below, possibly a case of Writer Gender Confusion, is that Snoop tends to change genders between books. The cat is definitely a male in the first four books, but has suddenly and without explanation become female in the fifth book. In subsequent books the cat switches between being male and female; at one point even switching from male to female within the course of one book, without anyone except the readers noticing. Could be cracked up to the fact that the writers Did Not Do the Research on continuity issues like this; it's fairly likely that, being anonymous ghostwriters, They Just Didn't Care.
As You Know: A peculiar version, as the narrator text sometimes repeats information that the audience already knows, providing recaps of information that happened earlier in the same book. It's especially blatant in the cases of Snoop and Snap -- whenever they appear on-page and haven't been mentioned for a while, the narrator almost always makes sure to inform the audiences that they are, in fact, a cat and a dog.
- Flossie and Freddie, especially in earlier books, tend to refer to Snoop as "our cat Snoop" or even "our black cat Snoop" when referring to him to the other members of the family, who should very well know that Snoop is a cat and that he's black. Might be justified in this instance, though, as Flossie and Freddie are small children -- it may very well make sense to them to talk like this.
The Bully: Danny Rugg, though exactly how bullying he is depends on the book. Sometimes he's on fairly civil terms with the Bobbsey twins, sometimes his entire life seems to revolve around playing mean-spirited pranks on them.
Color Coded for Your Convenience: Nan and Bert are darkhaired and thin. Freddie and Flossie are blonde and chubby.
Continuity Drift/Continuity Snarl: About as much as you'd expect for 72 books written over 76 years by dozens of authors. Pets and relatives appear and disappear or change sex (or even names; in one book Snap, the dog, all of a sudden becomes "Splash."). Characters change drastically in personality and lifestyle. The fact that time passes in the books but the characters stay the same age means that aspects of prior books become impossible or highly unlikely.
Ethnic Menial Labor: Sam and Dinah are black live-in servants to the Bobbsey family at the beginning of the series and spoke in thick accents. By the end of it, they were still black, but spoke much more clearly and it was implied that they drove in to work.
Follow the Leader: The success of the series led to the creation of "The Happy Hollisters", which (although the Hollisters were five kids, and none of the twins) copied a lot of the details, such as the small misadventures and scrapes occasionally leading into bigger mysteries, loving and involved parents, a resident "bad boy bully" who shows up to be mean from time to time, and even a cat and a dog.
- The Bobbseys themselves followed suit when fellow Stratemeyer Syndicate series, The Hardy Boys and Nancy Drew grew popular, and the Bobbsey books underwent a gentle Genre Shift to become a lot more about mysteries, hidden treasures and suspicious people pulling off strange schemes -- though with a couple of surprisingly Darker and Edgier examples very late in the series, it never really lost its "fun family adventures" tone.
Funetik Aksent: Sam and Dinah have very thick argot in the early books.

"Deed an' dat's whut she am!" exclaimed a fat, good-natured looking colored woman, smiling at the little girl. Dinah was the Bobbsey family cook. She had been with them so long that she used to say, and almost do, just what she pleased. "Dis am de forty-sixteen time I'se done bin down to de end ob de car gittin' Miss Flossie a drink ob watah. An' de train rocks so, laik a cradle, dat I done most upsot ebery time. But I'll git you annuder cup ob watah, Flossie lamb!"

In-Series Nickname: Mr. Bobbsey refers to the younger pair of twins as "my fat little fireman" and "my fat little fairy."
Sleepwalking: An early story involving Flossie seeing a ghost standing at the foot of her bed turns out to be Freddie sleepwalking.
Snooping Little Kid: In some books, the Bobbsey twins will show slight traces of this trope, though surprisingly for a Stratemeyer Syndicate series, it's most often averted -- nine times out of ten, the kids dump into mysteries completely by chance and even then they seldom go out of their way to investigate. Unless they suspect the culprit is Danny Rugg.
Theme Twin Naming: Averted with Bert and Nan, played straight with Freddie and Flossie.
Unto Us a Son and Daughter Are Born: Twice, even.