This sixteen volume series by Helen Wells and Julie Tatham was published by Grosset and Dunlap from 1947 to 1964. Vicki Barr experiences many thrilling adventures during her career as a flight stewardess.

The Trixie Belden series was published by the Whitman Publishing Company from 1948 to 1986. Trixie Belden attracts mysteries and trouble in all of her adventures, much to the chagrin of her fellow club members.

The Three Investigators series was published by Random House from 1964 to 1987. Jupiter, Pete, and Bob have their headquarters in the Jones Salvage Yard and specialize in solving difficult puzzles.

The Ruth Fielding series was published from 1913 through 1934 by Cupples and Leon. Ruth Fielding is the prototype for the girl sleuths who came later, including Nancy Drew, the Dana Girls, and Beverly Gray.

The Rick Brant series was published by Grosset and Dunlap from 1947 to 1968. Rick Brant and his pal Scotty solve mysteries and have thrilling adventures while using the latest scientific inventions.

This seventeen volume series by Mildred A. Wirt was published during the 1930s and 1940s. Irrepressible Penny Parker works as a newspaper reporter for her father's newspaper.

This Stratemeyer Syndicate series was published from 1913 to 1933 by Grosset and Dunlap. The Outdoor Girls have many thrilling adventures while they participate in a variety of outdoor activities.

The Nancy Drew series was first published in 1930 and is one of the most successful children's series of all time. Nancy Drew is a lawyer's daughter and solves mysteries with the help of her friends, Bess and George.

The Ken Holt series consists of 18 titles published from 1949 to 1963. Reporter Ken Holt and his photographer friend, Sandy Allen, work for the Brentwood Advance . The boys use their superior investigative skills to solve dangerous mysteries.

This eighteen volume series was published by several different companies from the 1930s to the 1980s. Sixteen year old Kay Tracey solves mysteries with her two friends Betty and Wilma.

The Famous Judy Bolton Mystery Stories were in print from 1932 until 1967. Author Margaret Sutton based each book on "something that actually happened." Unlike most series book characters, Judy Bolton ages as the series progresses and even gets married.

Always advertised as "by the author of the Nancy Drew books," this 34 volume series was published from 1934 to 1979. Louise and Jean Dana attend Starhurst School and solve mysteries at the same time.

This twelve volume series was written by Betty Cavanna under the pen name of Betsy Allen. It details the colorful adventures of career girl Connie Blair as she unravels mysteries related to her work.

This twenty-seven volume series was written by Helen Wells and Julie Tatham and was published by Grosset and Dunlap from 1943 to 1968. It follows the adventures of Cherry Ames throughout her nursing career.

This twelve volume series was published from 1925 to 1932. It follows the adventures of three sisters, Helen, Margy, and Rose Blythe, as they courageously battle poverty and misfortune.

In this thirteen volume series, Biff Brewster travels the world, learning about foreign culture and thwarting the communists. Biff's thrilling adventures are set in exotic locations.

This twenty-six volume series by Clair Blank was in print from 1934 until about 1955. It follows the exciting adventures of reporter Beverly Gray and her friends as they travel the world to many exotic places.

The Betty Gordon Series is an important early series that paved the way for Nancy Drew and Trixie Belden. This excellent series was published by Cupples and Leon for fifteen volumes from 1920 through 1932.

The Adventure Girls Series This three volume series written by Clair Blank, author of the Beverly Gray Mystery Stories, was released as a breeder set in 1936 by the A.L. Burt Company. The Arden Blake Mystery Series This three volume series was written by Cleo F. Garis and published by A. L. Burt in 1934. Arden and her chums solve a few mysteries while they attend Cedar Ridge College.

The Barbara Ann Series This four volume series was written by Ruth Grosby and was published from 1939 to 1942 by Grosset and Dunlap. Barbara Ann Wilson solves mysteries as she attends high school and college. The Billie Bradley Series This nine volume Stratemeyer Syndicate series tells the story of Billie Bradley, who attends a boarding school with her friends. This series is one of several important forerunners to the Nancy Drew series.

The Brains Benton Series This six volume series was the forerunner to the Three Investigators series. Brains Benton and his partner, Jimmy Carson, run a detective agency out of a secret room in a garage. The Bret King Mystery Series This nine volume series follows the adventures of Bret King and his cowboy friends. The boys of Rimrock Ranch savor western life as they bring desperate outlaws to justice.

The Doris Force Mystery Stories This four volume series from 1931 was written jointly by Mildred A. Wirt Benson and Walter Karig. Doris Force is a typical Stratemeyer Syndicate heroine who has more than her share of bizarre adventures. The Girl Scouts Mystery Series This six volume series by Virginia Fairfax follows the adventures of a group of Mississippi Girl Scouts as they enjoy camping, solving a few mysteries, and living the outdoor life.

The Girl Scouts Series This ten volume series by Edith Lavell was published by A. L. Burt during the 1920s. The series follows the achievements of Marjorie Wilkinson in the Girls Scouts from her freshman year in high school until after her college graduation. The Girls of Central High This Stratemeyer Syndicate series was published from 1914 to 1919 by Grosset and Dunlap. It follows a group of girls who participate in the interschool athletic league.

The Linda Carlton Series This five volume series by Edith Lavell was published by A. L. Burt and is one of the most difficult to find Burt series. Linda Carlton is an aviatrix who has more than her share of harrowing escapes and is plagued by false accusations and extortion attempts. The Mary Lou Series This three volume series by Edith Lavell was published by A. L. Burt in 1935. Styled after the original Nancy Drew, Mary Louise Gay is a bold girl detective whose methods are sometimes not strictly legal.

Melody Lane Mystery Stories This nine volume series by Lilian Garis is set on a country road named Melody Lane. The stories detail the lives of people who live on or near Melody Lane and the mysteries they encounter. Mexican Mystery Stories for Girls This three volume series by Helen Randolph was published in 1936 by A. L. Burt. The series follows the adventures of three girls as they explore Mexico.

The Mill Creek Irregulars Wisconsin author August Derleth wrote ten volumes about the adventures of Steve Grendon and Sim Jones. Steve has a knack for finding mystery, and Sim is his reluctant companion. The Moving Picture Girls Series This seven volume Stratemeyer Syndicate series was published from 1914 to 1916 by Grosset and Dunlap. Ruth and Alice DeVere work as actresses in a moving picture company and have many exciting adventures.

Peggy Lane Theater Stories This well-written series by Virginia Hughes ran for a short eight titles from 1962 to 1965. The richly descriptive prose gives detailed insight into the theatrical world and draws the reader into Peggy's life, making her experiences seem almost real. Perry Pierce Mystery Stories This four volume Stratemeyer Syndicate series from the early 1930s follows the adventures of Perry Pierce and the Skull Mystery Club as they solve mysteries and bring criminals to justice.

The Riddle Club Series This six volume Stratemeyer Syndicate series was published by Grosset and Dunlap during the 1920s. The Riddle Club consists of six friends who solve challenging riddles and have the best of times together. The Roger Baxter Series The Roger Baxter series was written by the authors of the Ken Holt series. This excellent series follows the adventures of Roger and Bill Baxter as they solve mysteries with government agent, Slim Warner.