Anne Perry (I haven't read any of her novels.)
THOMAS & CHARLOTTE PITT Series:
Main Characters: Thomas & Charlotte, Police Inspector & Wife, London, Victorian

1. The Cater Street Hangman   '79
2. Callander Square   '80
3. Paragon Walk     '81
4. Resurrection Row     '81
5. Rutland Place    '83
6. Bluegate Fields     '84
7. Death in Devil’s Acre     '85
8. Cardington Crescent     '87
9. Silence in Hanover Close    '88
10. Bethlehem Road    '90
11. Highgate Rise    '91
12. Belgrave Square    '92
13. Farrier's Lane    '93
14. The Hyde Park Headsman    '94
15. Traitor’s Gate    '95
16. Pentecost Alley     '96
17. Ashworth Hall     '98
18. Brunswick Gardens    '98
19. Bedford Square     '99
20. Half Moon Street     '00
21. The Whitechapel Conspiracy     '01
22. Southampton Row    '02
23. Seven Dials     '03
24. Long Spoon Lane    '05  
25. Buckingham Palace Gardens     '08

WILLIAM MONK Series:
Main Character: William Monk, Victorian London Police Inspector

1. The Face of a Stranger     '90
2. A Dangerous Mourning     '91
3. Defend and Betray    '92
4. A Sudden, Fearful Death    '93
5. Sins of the Wolf    '94
6. Cain His Brother    '95
7. Weighed in the Balance    '97
8. The Silent Cry     '97
9. A Breach of Promise     '98
10. The Twisted Root    '99
11. Slaves of Obsession     '00
12. Funeral in Blue    '01
13. Death of a Stranger    '02
14. The Shifting Tide    '04
15. Dark Assassin    '06
16. Execution Dock    '09

WORLD WAR I: MATTHEW REAVLEY Series:

1. No Graves as Yet    '03
2. Shoulder the Sky    '04
3. Angels in the Gloom    '05  
4. At Some Disputed Barricade      '06
5. We Shall Not Sleep      '07

CHRISTMAS Series:

A Christmas Journey    '03
A Christmas Visitor    '04
A Christmas Guest    '05
A Christmas Secret    '06 
A Christmas Beginning    '07
A Christmas Grace    '08
A Christmas Promise    '09

An Anne Perry Christmas     '06 (Includes A Christmas Journey & A Christmas Visitor)
Anne Perry's Christmas Mysteries   '08 (Includes A Christmas Guest & A Christmas Secret)  
Silent Nights    '09 (Includes A Christmas Beginning & A Christmas Grace)

STAND ALONES:

Malice Domestic 6      '97  (Anthology)
Tathea    '97
A Dish Taken Cold   '01
Death by Horoscope   '01   (Anthology)
Much Ado About Murder: All-New Shakespeare-Inspired Mystery Stories    '02
Come Armageddon    '03 (Sequel to Tathea)
Death by Dickens    '04  (Anthology)