The Bat is a three-act play by Mary Roberts Rinehart and Avery Hopwood that was first produced by Lincoln Wagenhals and Collin Kemper in 1920.

The story combines elements of mystery and comedy as Cornelia Van Gorder and guests spend a stormy night at her rented summer home, searching for stolen money they believe is hidden in the house, while they are stalked by a masked criminal known as "the Bat".

Elderly, single Cornelia Van Gorder is renting an old, isolated Long Island mansion owned by the estate of Courtleigh Fleming, a bank president who had reportedly died several months before.

They tell Cornelia that Jack Bailey, a cashier at Fleming's bank, has disappeared and is suspected of stealing over a million dollars.

Reginald recognizes Jack, and the exposure of her fiancé makes Dale admit that she gave Wells the blueprint with the hidden room.

Before Wells can go to the hidden room, a stranger claiming to have lost his memory after he was attacked and tied up in the garage appears at the terrace door.

The third act begins on the upper floor of the house, where a masked man is seen in the previously-hidden room taking a money bag from a safe.

Cornelia begins to present an alternative theory, but is interrupted when the unknown man comes upstairs and Anderson asks him about his amnesia.

[3] After starting her writing career with short stories, she achieved popular success with the publication of her 1908 novel The Circular Staircase.

[3][4] In 1909 Broadway producers Lincoln Wagenhals and Collin Kemper asked Rinehart to adapt her novella Seven Days for the stage.

[7][9] After Rinehart returned in 1919, Hopwood joined her in Sewickley, Pennsylvania, where she lived; they worked on the play there and in New York City until they completed it.

[10][13] Rinehart decided to focus on family obligations and missed the reading of the play to Wagenhals and Kemper, who expressed interest in staging it after Hopwood shared a draft with them.

The first revival, produced by Ben Lundy and directed by Benjamin F. Kamsler, opened on May 31, 1937, at the Majestic Theatre as part of a summer-stock program.

Despite The Bat's unusually long run, Ellsler appeared in almost every performance (including the evening after she heard about her husband's death); she left the part only briefly, after collapsing onstage during the production's final week.

They did not show Hunter or the other cast members the final scene (in which the Bat's identity is revealed) until shortly before the dress rehearsal.

Productions of The Bat included the initial Broadway run, a production in London's West End and two later Broadway revivals, with the following opening-night casts: To adapt The Circular Staircase for the stage, Rinehart and Hopwood made changes to the characters and plot; the most significant was the addition of the flamboyant criminal whose pseudonym became the play's title.

The character names were all changed (Rachel Innes in the novel became Cornelia Van Gorder in the play, her niece Gertrude became Dale, etc.

[34] To maintain plausibility, Rinehart and Hopwood checked the timing of the plot (including events taking place offstage) and rewrote as needed to ensure the timeline was realistic.

[35] With a multi-year Broadway run, over nine months on the West End and several road companies touring concurrently, The Bat was a financial success.

In his 1946 profile of Rinehart, Life magazine writer Geoffrey T. Hellman estimated that the play had earned over nine million dollars.

Broun wrote that The Bat "provided an excellent succession of thrills", although the "interludes of low comedy" with Vokes could have been omitted.

In The Spectator, W. J. Turner wrote that the play was thrilling and praised Moore's acting as Cornelia, but disliked Wills's "buffoonery" as Lizzie.

[38][50] The Bat's success encouraged imitators to set mysteries mixed with comedy in old, dark houses which some of the characters think are haunted.

By the late 1920s, the mysteries' popularity was declining in live theater, although the genre continued in films such as James Whale's The Old Dark House (1932) and several adaptations of The Bat.

Critics considered The Bat to be an improvement over that previous film; it received positive reviews and did well at the box office.

[64] The remake, released by United Artists on November 29, 1930, starred Chester Morris as the Bat and Una Merkel as Dale; British actress Grayce Hampton played Cornelia.

Dr. Wells (played by horror star Vincent Price) had a more prominent role, and Agnes Moorehead co-starred as Cornelia.

The WOR-TV anthology series Broadway Television Theatre aired its version on November 23, 1953, with a cast that included Estelle Winwood, Alice Pearce and Jay Jostyn.

[72] On July 30, 1978, the West German network Hessischer Rundfunk broadcast a television movie version entitled Der Spinnenmörder [de].

The comic significantly altered the story to make Cornelia Van Gorder younger and give her an evil twin who is the murderer.