Swedish writer and journalist, who published with his wife Maj Sjöwall the widely translated series novels of Martin Beck and his colleagues at the Central Bureau of Investigation in Stockholm. Its style has been described as "reportal... spare, disciplined and full of sharply observed detail..." The critic and awarded mystery writer H.R.F. Keating selected Roseanna (1965) in 1987 for his list of the one hundred best crime novels. Several of the books have also been adapted into screen.

"Elofsson was following the normal procedure. He had grabbed the boy's jacket with both hands. The next step was to pull the victim closer and drive his right knee into the man's groin. And that would take care of that. The same way he had done it so many times before. Without firearms." (from Cop Killer, 1974)

Per Wahlöö was born in Göteborg, the son of Waldemar and Karin (Svensson) Wahlöö. After graduating from the University of Lund in 1946, he worked as a journalist, covering criminal and social issues for a number of newspapers and magazines. In the 1950s Wahlöö was engaged in radical political causes, activities that resulted in his deportation from Franco's Spain in 1957. Before becoming a full-time writer, he wrote a number of television and radio plays, and was managing editor of several magazines.

As a novelist Wahlöö made his debut with Himmelsgeten (1959), which was followed by others dealing with abuses of power and the dark side of the society. Wahlöö's science fiction thrillers include Mord på 31 (1965, The Thirty-first Floor), which was filmed as Kamikaze 1989, starring the director Rainer Werner Fassbinder in his final screen role. The story was set in a futuristic Germany. Stälspranget (1968, Steep Spring) depicted a deadly plague in Sweden. The protagonist in both novels was Chief Inspector Jensen. Generalerna (1965), a trial novel set in a military state, reflected Wahlöö's views on dictatorship. Lastbilen (1962) was published in the United States as A Necessary Action and in Britain as The Lorry. Uppdraget (1963), set in a Latin American country, gained an international success. It was translated into English under the title The Assignment.

In 1961 Wahlöö met Maj Sjöwall when they were working for magazines published by the same company. At that time Wahlöö was married, Sjöwall was a single parent of a daughter. They became lovers and married. The carefully planned crime novel series, with the undertitle "roman  om ett brott" (the story of a crime), was created in the evenings, after their children had been put to bed. Starting from Roseanna (1965), their project ended ten years and ten books later with Terroristerna (1975). According to Wahlöö, their intention was to "use the crime novel as a scalpel cutting open the belly of the ideological pauperized and morally debatable so-called welfare state of the bourgeois type." The narrative focused on realistic police routine and teamwork – rather the deductive leaps of a Hercule Poirot type individual – and was compared to Georges Simenon.

The first three novels, Roseanna, a story of rape-murder of an American girl whose body in found in a Swedish canal, The Man Who Went Up in Smoke (1966) and The Man on the Balcony (1967), were straightforward police procedural novels. They introducing the central characters – the solid, methodical detective Martin Beck with failing marriage, ex-paratrooper Lennart Kollberg, who hates violence and refuses to carry a gun, Gunvald Larsson, wildman and a drop-out from high society, Einar Rönn from the rural north of Sweden and patrolmen Kristiansson and Kvant, the necessary comic pair. Beck considers himself "stubborn and logical, and completely calm". He lives in a small apartment in Stockholm with his wife, Inga, and two children. In the following books Beck's relationship with his wife deteriorates, and he begins an affair with the liberal Rhea Nilsen.

The Laughing Policeman (1968), about the investigation of the murder of eight occupants of a Stockholm bus, was adapted to screen in 1973, directed by Stuart Rosenberg and starring Walter Matthau, Bruce Dern, and Lou Gossett. The story was set in San Francisco. The film shared its Bay area locale with Dirty Harry (1971), but was otherwise more downbeat. By coincidence, Bo Widerberg, who made a film adaptation of the novel The Abominable Man, entitled Mannen på taket (1976), had lived in Malmö in the same building than Wahlöö's first wife Inger Wahlöö.

At the end of The Locked Room (1972), Sjöwall and Wahlöö show their sympathy towards a bank robber; however, they abhor sexual violence. In Cop Killer (1974) Lennart Kollberg writes his resignation, because of his socialist world view. The later novels, and especially the last, The Terrorist, is a bitter analysis of the welfare state, and openly sides with criminals-as-revolutionaries. Beck is deeply ambivalent about remaining a policeman, because he fears that he is contributing to the violent nature of Swedish society rather than preventing it. The novel was published after Wahlöö's death in Stockholm on June 23, 1975. Though a joint venture, the book was mostly written by Wahlöö, who was already very ill.

Wahlöö's other works include translations into Swedish of some Ed McBain's 87th Precinct procedural novels and Noel Behn's political thriller The Kremlin Letter, filmed by John Huston in 1970. With Sjöwall he also edited the literature magazine Peripeo, and wrote a comparative study of police methods in Sweden, the United States, Russia, and England. "He was an extreme Left-winger with a taste for popular sport," said the English mystery writer Julian Symons of Wahlöö, "and his interest in British football... was passionate. The books he wrote with Maj Sjöwall represents an attempt to bring his political feelings into a literary form with a wide appeal."

For further reading: 'Roman om en forbrydelse' - Sjöwall/Wahlöö's verk og virkelighed by Ejgil Søholm (1976); Encyclopedia of Mystery and Detection, ed. by Chris Steinbrunner and Otto Penzler (1976); 'The Police in Society: The Novels of Maj Sjöwall and Per Wahlöö' by Frank Occhiogrosso, in The Armchair Detective, no. 2 (1979); Wold Authors 1970-1975, ed. by John Wakeman (1980); The Police Procedural by George Dove (1982); Lystmord, ed. by Jørgen Holmgaard and Bo Tao Michaëlis (1984); Polemical Pulps by J. Kenneth Van Dover (1993); 'Maj Sjöwall and Per Wahlöö' by Nancy C. Mellerski and Robert P. Winston, in Mystery and Suspense Writers, ed. by Robin W. Winks (1998) - Note: The Laughing Policeman won the best novel Edgar Award in 1971 from the Mystery Writers of America. - See also: Lawrence Treat, the creator of modern police procedural novels.

Selected works:

• Himmelsgeten, 1959 (reprinted as Hövdingen in 1967)
  - TV mini-series 1986, prod. Sveriges Television (SVT), dir. Lars-Göran Pettersson, starring Sten Ljunggren, Göran Engman, Gösta Engström, Lisa Hugoson, Bo Lindström, Tomas Nordström, Bert-Åke Varg
• Vinden och regnet, 1961
• Lastbilen, 1962
  - The Lorry (UK title; tr. Joan Tate, 1968) / A Necessary Action (US title; tr.  Joan Tate, 1969)
  - film: Mannen i skuggan, 1978, prod. Jadran Film, Stockholm Film, dir. Arne Mattson, starring Helmut Griem, Slobodan Dimitrijevic and Gunnel Fred   
• Uppdraget, 1963
  - The Assignment (tr. Joan Tate, 1966)
  - film 1977, prod. by Nordisk Tonefilm, Svensk Filmindustri (SF), Svenska Filminstitutet (SFI), dir. by Mats Arehn, starring Christopher Plummer, Thomas Hellberg, Fernando Rey, Carolyn Seymour
• Mord på 31:a våningen, 1964
  - The Thirty-First Floor (US title; tr. Joan Tate, 1967) / Murder on the Thirty-First Floor (Pantheon Books; tr. Joan Tate, 1982)  
  - films: 31. osakonna hukk, 1980, prod. Gosteleradio, Tallinnfilm, dir. Peeter Urbla, starring  Lembit Ulfsak (as Jensen), Ivan Krasko and Enn Klooren;  Kamikaze 1989, 1982, prod. Oase Filmproduktion, Regina Ziegler Filmproduktion, Trio Film, dir. by Wolf Gremm, starring Rainer Werner Fassbinder (as Polizeileutnant Jansen), Günther Kaufmann, Boy Gobert, Arnold Marquis
• Det växer inga rosor på Odenplan, 1964
• Idole, 1965 (TV play, with Arvid Rundberg)
  - dir. by Håkan Ersgård, starring Erik Hell, Lars Passgård, Inga Gill, Elsa Textorius, Fritz Svanberg 
• Generalerna, 1965
  - The Generals (tr. Joan Tate, 1974)
• Flygplan saknas, 1965 (screenplay (with Arvid Rundberg)
  - film prod. by Nordik Tonefilm, dir. by Per Gunvall, starring Olle Johansson, Birgit Nordin and Runar Martholm  
• Morianerna, 1965 (screenplay with Jan Ekström, Arne Mattsson)
  - film prod. Bison Film, dir. by Arne Mattsson, starring  Anders Henrikson, Eva Dahlbeck, Heinz Hopf, Elsa Prawitz 
• Nattmara, 1965 (screenplay with Arne Mattson)
  - film prod. Svensk Filmindustri (SF), dir. by Arne Mattson, starring  Ulla Jacobsson, Gunnar Hellström, Sven Lindberg, Mimi Pollak 
• Mördaren - en helt vanlig person, 1967 (screenplay with Arne Mattson, Maj Sjöwall)
  - film prod. by A-Produktion, dir. by Arne Mattson, starring Allan Edwall, Lars Ekborg, Britta Pettersson, Karl-Arne Holmsten, Erik Hell, Heinz Hopf  
• Stålsprånget, 1968
  - The Steel Spring (tr. Joan Tate, 1970)

With Maj Sjövall:

• Roseanna, 1965
  - Roseanna (tr. Lois Roth, 1967)
  - Roseanna: romaani rikoksesta (suom. Kari Jalonen, 1969)
  - film adaptations: 1967, prod. Independent film, dir. Hans Abramson, starring Keve Hjelm (as Martin Beck), Hans Ernback, Tor Isedal, Gio Petré, Hans Bendrik; 1993, prod. Nordisk Film- & TV-Fond, Rialto Film, Svensk Filmindustri (SF), dir. Daniel Alfredson, starring Gösta Ekman (as Beck), Kjell Bergqvist, Rolf Lassgård, Anna Helena Bergendal
• Mannen som gick upp i rök, 1966
  - The Man Who Went Up in Smoke (tr. Joan Tate, 1969)
  - Mies joka hävisi savuna ilmaan (suom. Kari Jalonen, 1967)
  -  film adaptation: Mann, der sich in Luft auflöste, 1980, prod. Andre Libik, Europa Film, Mafilm 'Dialog' Studio, dir. Péter Bacsó, starring Derek Jacobi (as Martin Beck), Judy Winter, Tomas Bolme, Lasse Strömstedt, Sándor Szabó
• Mannen på balkongen, 1967
  - The Man on the Balcony (tr. Alan Blair, 1968)
  - Mies parvekkeella (suom. Margit Salmenoja, 1980)
  -  film adaptation: Mannen på balkongen, 1993, prod. Nordisk Film- & TV-Fond, Rialto Film, Svensk Filmindustri (SF), dir. by Daniel Alfredson, starring Gösta Ekman (as Martin Beck),  Kjell Bergqvist, Rolf Lassgård, Niklas Hjulström, Bernt Ström
• Den skrattande polisen, 1968
  - The Laughing Policeman (tr. Alan Blair, 1970)
  - Bussimurha (suom. Kari Jalonen, 1972)
  -  film adaptation in 1973, prod. Twentieth Century Fox Film Corporation, dir. by Stuart Rosenberg, starring Walter Matthau, Bruce Dern, Louis Gossett Jr., Albert Paulsen. Note: the locale was shifted from Sweden to San Francisco when it was filmed.
• Brandbilen som försvann, 1969
  - The Fire Engine That Disappeared (tr. Joan Tate, 1970)
  - Kadonnut paloauto (suom. Margit Salmenoja, 1980)
  -  film adaptation: 1993, prod. Nordisk Film- & TV-Fond, RTL, Rialto Film, dir. by Hajo Gies, starring Gösta Ekman (as Martin Beck), Kjell Bergqvist, Rolf Lassgård, Niklas Hjulström, Holger Kunkel
• Polis, polis, potatismos!, 1970
  - Murder at the Savoy (tr. Amy and Ken Knoespel, 1971)
  - Missä viipyy poliisi (suom. Marja-Riitta Ritanoro ja Kari Jalonen, 1974)
  - films: Nezakonchennyy uzhin, 1980, dir. Janis Streics, starring Romualds Ancans (as Martin Beck), Ingrid Andrina, Lilita Berzina, Ivars Kalnis; 1993, prod. Nordisk Film- & TV-Fond, Rialto Film, Svensk Filmindustri (SF) dir. Per Berglund, starring Gösta Ekman, Kjell Bergqvist and Rolf Lassgård  
• Den vedervärdige mannen från Säffle, 1971
  - The Abominable Man (tr. Thomas Teal, 1972)
  - Komisario Beck tähtäimessä (suom. Marja-Riitta Ritanoro ja Kari Jalonen, 1974)
  -  film adaptation: Mannen på taket, 1976, prod. Svensk Filmindustri (SF), Svenska Filminstitutet (SFI), dir. by Bo Widerberg, starring Carl-Gustaf Lindstedt, Sven Wollter, Thomas Hellberg, Håkan Serner, Ingvar Hirdwall 
• Det slutna rummet, 1972
  - The Locked Room (tr. Paul Britten Austin, 1973)
  - Suljettu huone (suom. Kari Jalonen) - film adaptation: De gesloten kamer, 1993, prod. Filmcase, Prime Time, dir. by Jacob Bijl, starring Jan Decleir (as Martin Beck), Els Dottermans, Warre Borgmans, Jakob Beks
• Polismördaren, 1974
  - Cop Killer (tr. Thomas Teal, 1975)
  - Poliisimurha (suom. Kari Jalonen, 1978)
  -  film adaptation in 1993, prod. Rialto Film, Svensk Filmindustri (SF), Sveriges Television (SVT), dir. by Peter Keglevic, starring Gösta Ekman (as Martin Beck), Kjell Bergqvist, Rolf Lassgård, Tomas Norström, Johan Widerberg 
• Terroristerna, 1975
  - The Terrorists (tr. Joan Tate, 1976)
  - Terroristit (suom. Margit Salmenoja, 1980)
  - film adaptation: Stockholm Marathon, 1993, prod. Rialto Film, Svensk Filmindustri (SF), Sveriges Television (SVT), dir. by Peter Keglevic, starring Gösta Ekman (as Martin Beck), Kjell Bergqvist, Rolf Lassgård, Niklas Hjulström, Corinna Harfouch
• Sista resan och andra berättelser, 2007