Trixie Belden is the title character in a series of 'girl detective' mysteries written between 1948 and 1986. The first six books were written by Julie Campbell Tatham, who also wrote the Ginny Gordon series, then continued by various in-house writers from Western Publishing under the pseudonym Kathryn Kenny. Today the rights to the series are owned by Random House. The series was completely out of print for a number of years, but Random House began releasing a new edition of the books in summer of 2003. As of summer, 2006, volumes 1-15 have been reissued. Fans of the series hope to see all thirty-nine volumes reprinted, especially the hard-to-find volumes 35-39.
Trixie is a young teen living just outside the fictional town of Sleepyside-on-Hudson, in the Hudson River Valley area of New York. She lives at Crabapple Farm, which had been in her family for either three or six generations (this varies between books), with her parents and three brothers, Brian, Mart, and Bobby. The first book establishes her friendship with lonely, sheltered rich girl Honey Wheeler whose family has just moved into the Manor House next door and soon the girls are embroiled in their first case.
Throughout the series, the two girls solve mysteries that baffled authorities and, along with brothers and friends, formed a club called the Bob-Whites of the Glen, have adventures, travel (though not as extensively as Nancy Drew, an older and more sophisticated girl sleuth), and struggle with school. Trixie had particular difficulties with math.
With the advent of internet fan-supported websites, many Trixie Belden related sites have been created. On many of these sites, comparisons are made between Trixie and Nancy Drew. Fans of Trixie Belden usually cite her more realistic persona as a teenager who grumbles about chores and is often frustrated by life with both older and younger brothers. Trixie also experiences some insecurity about her looks, often comparing herself unfavorably with her friends, Honey and Diana, who are regarded as more obviously attractive. On some sites, there is a tradition of regarding Nancy Drew's character as a persona non grata. She is facetiously referred to as "Nancy Who?"
Main characters 
The ages indicated refer to each character's age at the beginning of the series.
- Beatrix "Trixie" Belden: Thirteen-year-old Trixie Belden is one of the two co-presidents of the Bob-Whites of the Glen. Described as being short with a sturdy build, she has short blonde ringlets (either sandy blonde or strawberry blonde depending on edition) and round blue eyes. She has a tendency to jump to conclusions, but her hunches often prove to be correct. One of Trixie's chores is to take care of six-year-old Bobby and, while she loves her little brother, she often loses patience with the mischievous child. She and Honey plan to one day open their own business: The Belden-Wheeler Detective Agency. Trixie has an amazing instinct for people and can accurately judge them before she gets to know them. Her best friends are Honey Wheeler and Di Lynch.
- Madeleine G. "Honey" Wheeler: Depending on the book, thirteen-year old Honey Wheeler is either vice-president or secretary of the Bob-Whites of the Glen. She is described as being tall, slender, and pretty, with shoulder-length golden-brown hair and large hazel eyes. Until moving to Sleepyside, she spent her life in boarding schools and summer camps barely knowing her own parents. Her friendship with Trixie and the Bob-Whites has given her more confidence and helped her to forge a relationship with her parents and adopted brother. Generally regarded as the sweetest and most tactful of the Bob-Whites, she is also their star swimmer. She now attends Sleepyside Junior-Senior High School with the rest of the Bob-Whites, where she consistently receives high marks and praise. Honey and Brian seem to like each other, although Brian is about three years older.
- James '"Jim" Winthrop Frayne II : Fifteen-year-old Jim Frayne is the other co-president of the Bob-Whites of the Glen. The focus of the first two books, he is adopted by the Wheelers at the end of "The Red Trailer Mystery", after successfully running away from his abusive stepfather. He has a Springer spaniel named Patch. He is described as having red hair and green eyes, coincidentally the same coloring as his adoptive father, Matthew Wheeler. Jim is an expert horseman and 'rides like a centaur'. He and Trixie have a fondness for one another and Jim gives Trixie an orchid and later his ID bracelet; however, the romantic angle is downplayed in later volumes. His goal is to one day use his inheritance to build a school for orphaned boys that will combine outdoor–naturalist activities with regular academics. Throughout the series, there is some inconsistency regarding his age.
- Brian Belden: Brian Belden, sixteen, is the oldest of the four Belden children. Described as dark and handsome, he is by far the most level-headed of the seven Bob-Whites and plans to become a doctor after finishing school. Throughout the series, Brian often provides first aid to his sister, Trixie, as well others who are injured during the course of the Bob-Whites' adventures. Brian is very smart and mature, always the voice of reason and always trying to keep Trixie out of trouble. In the fifth book, Brian got his first car: an old jalopy which he purchased from Mr. Lytell, a storekeeper, for fifty dollars. Brian's first aid skills stretch to caring for automobiles, as he is often shown working on his car, and also to animals as when he is given responsibility to bandage an injured horse owned by the Wheelers.
- Martin "Mart" Belden: Exactly eleven months older than Trixie, fourteen-year-old Martin Belden is often described as Trixie's 'almost-twin'. Mart is most well known for his love of eating and his out-sized vocabulary. He has a crush on Diana Lynch. He has a fondness for Cosmo McNaught space adventures books and in one book, bickers with Trixie that Cosmo is better than Lucy from the Lucy Radcliff books Trixie likes so much. He plans to become a farmer, although the Pet Show Mystery gave him an interest in computers. Despite his frequent arguments with his sister (they are constantly teasing and picking on each other), the two are quite close.
- Diana "Di" Lynch: The prettiest girl in class, thirteen-year-old Diana Lynch has black hair and violet eyes (possibly due to the popularity of Elizabeth Taylor as a young actress at the time Diana's character was created.) She has both a set of twin brothers and a set of twin sisters who are much younger than herself. Her father recently made a lot of money, and Di hates being rich, though the Bob-Whites help her adjust. She joins the Bob-Whites in the Mysterious Visitor, while inadvertently providing them with another mystery. She shows great artistic ability in later books and can be a bit gullible at times. She is not the most intelligent, but is a good sport, smiling and laughing often, especially at herself when she makes mistakes. One consistent character trait established over the many stories is Di's love of the color purple.
- Daniel "Dan" Mangan: Orphaned in New York City, Dan Mangan, left to his own devices, became mixed up in a street gang called ‘The Cowhands’. The juvenile court sends him to live with his uncle Regan, the Wheelers' groom, in Sleepyside, although he actually lives and works for Mr. Maypenny, the gamekeeper. After a rough start in Sleepyside, Dan reformed and became the seventh Bob-White in the Black Jacket Mystery. His age is unknown; he begins school in Mart's homeroom, but later must study during vacations to keep up with classes he takes with Brian and Jim. He intends to be a police officer in New York City.
Supporting characters 
- Helen Belden (Moms): Trixie's mother, a kind and sensible homemaker. She loves her children and keeps them honest.
- Peter Belden (Dad): Trixie's father, a smart, honest, and generous man. He works at the Sleepyside bank, and loves his family very much.
- Robert "Bobby" Belden: The youngest Belden is only six when the series starts. He is darling, but very accident prone and gets into trouble often. Trixie babysits Bobby for allowance, so she often has to check in on him and read him stories when she'd much rather be solving a mystery.
- Reddy: The Belden's Irish Setter. He's beautiful and affectionate, but completely untrained.
- Miss Trask: She worked as a Math teacher at Honey's old boarding school, but Honey liked her so much Mr. Wheeler hired her to be Honey's governess. Now she mostly manages the estate. Smart, sensible and efficient, the Bob-Whites love Miss Trask, and she loves them. Miss Trask often accompanies the kids when they travel.
- Bill Regan: The hot-headed but good-natured groom. In the first book he taught Trixie to ride horses, and has been well loved by all the Bob-Whites since. Twenty-two in the first book (though he seems older), Regan is a good friend to the Bob-Whites, always helping out when they need him. He seems to have a love interest as seen in The Mystery at Saratoga. He takes in his late sister's son, Dan Mangan, and brings him from New York City, to live in Sleepyside, with Mr. Maypenny as Mr. Maypenny's helper.
- "Trixie Belden | Books". Randomhouse.com. Retrieved 2011-04-05.
- Campbell, Julie (1951). The Gatehouse Mystery. Racine, Wisconsin: Whitman Pub. Co. ISBN 0-375-82579-7.
- Shontz, Lori (June 11, 2003). "Waiting for Trixie Belden." The Pittsburgh Post-Gazette. Accessed November 2011.
- "Al E. Gator's Tales." (November 11, 1986). "Al's Favorite Books are also Popular with Al's Friends." The Lakeland Ledger. Accessed November 2011.
Here are the titles of the 39 books
1. The Secret of the Mansion
2. The Red Trailer Mystery
3. The Gatehouse Mystery
4. The Mysterious Visitor
5. The Mystery Off Glen Road
6. The Mystery in Arizona
7. The Mysterious Code
8. The Black Jacket Mystery
9. The Happy Valley Mystery
10. The Marshland Mystery
11. The Mystery at Bob-White Cave
12. The Mystery of the Blinking Eye
13. The Mystery on Cobbett's Island
14. The Mystery of the Emeralds
15. The Mystery on the Mississippi
16. The Mystery of the Missing Heiress
17. The Mystery of the Uninvited Guest
18. The Mystery of the Phantom Grasshopper
19. The Mystery of the Unseen Treasure
20. The Mystery Off Old Telegraph Road
21. The Mystery of the Castaway Children
22. The Mystery at Mead's Mountain
23. The Mystery of the Queen's Necklace
24. The Mystery at Saratoga
25. The Sasquatch Mystery
26. The Mystery of the Headless Horseman
27. The Mystery of the Ghostly Galleon
28. The Hudson River Mystery
29. The Mystery of the Velvet Gown
30. The Mystery of the Midnight Marauder
31. The Mystery at Maypenny's
32. The Mystery of the Whispering Witch
33. The Mystery of the Vanishing Victim
34. The Mystery of the Missing Millionaire
35. The Mystery of the Memorial Day Fire
36. The Mystery of the Antique Doll
37. The Pet Show Mystery
38. The Indian Burial Ground Mystery
39. The Mystery of the Galloping Ghost