The Simple Deep Space Nine Reading Lists are just my subjective versions of several condensed suggested reading lists, depending on the number of  books you might want to get.  Below are the top ten, twenty, thirty, forty, and fifty Deep Space Nine novels you should read.

Note that there is an omnibus, Twist of Fate, which includes Avatar, Books 1 and 2, Section 31: Abyss, Gateways: Demons of Air and Darkness, and that novel's concluding short story, "Horn and Ivory".  There is also an omnibus, These Haunted Seas, which collects the first two novels in the Mission: Gamma series.

CLICK HERE FOR THE FULL READING LIST.
Ten Series Era Novels

  1. Terok Nor: Day of the Vipers
  2. Terok Nor: Night of the Wolves
  3. Terok Nor: Dawn of the Eagles
  4. The Long Night
  5. The 34th Rule
  6. Tales of the Dominion War
  7. Hollow Men
  8. Prophecy and Change
  9. The Lives of Dax
  10. A Stitch in Time

The Essential Post-Finale Storyline

  1. Avatar, Book One
  2. Avatar, Book Two
  3. Section 31: Abyss
  4. Gateways: Demons of Air and Darkness
  5. Mission: Gamma- Twilight
  6. Mission: Gamma- This Gray Spirit
  7. Mission: Gamma- Cathedral
  8. Mission: Gamma- Lesser Evil
  9. Rising Son
  10. Unity

Twenty Novel Version
(With Focus on the Series Era)

  1. Terok Nor: Day of the Vipers
  2. Terok Nor: Night of the Wolves
  3. Terok Nor: Dawn of the Eagles
  4. Fallen Heroes
  5. The Long Night
  6. The 34th Rule
  7. Tales of the Dominion War
  8. Hollow Men
  9. Prophecy and Change
  10. The Lives of Dax
  11. Avatar, Book One
  12. Avatar, Book Two
  13. Section 31: Abyss
  14. Gateways: Demons of Air and Darkness
  15. Mission: Gamma- Twilight
  16. Mission: Gamma- This Gray Spirit
  17. Mission: Gamma- Cathedral
  18. Mission: Gamma- Lesser Evil
  19. Rising Son
  20. Unity

Twenty Novel Version
(With Focus on the Post-Finale Era)

  1. The Lives of Dax
  2. The Left Hand of Destiny, Book One
  3. The Left Hand of Destiny, Book Two
  4. A Stitch in Time
  5. Avatar, Book One
  6. Avatar, Book Two
  7. Section 31: Abyss
  8. Gateways: Demons of Air and Darkness
  9. Mission: Gamma- Twilight
  10. Mission: Gamma- This Gray Spirit
  11. Mission: Gamma- Cathedral
  12. Mission: Gamma- Lesser Evil
  13. Rising Son
  14. Unity
  15. Worlds of Deep Space Nine: Volume One
  16. Worlds of Deep Space Nine: Volume Two
  17. Worlds of Deep Space Nine: Volume Three
  18. Warpath
  19. Fearful Symmetry
  20. The Soul Key

Thirty Novel Version
(With Focus on the Series Era)

  1. Terok Nor: Day of the Vipers
  2. Terok Nor: Night of the Wolves
  3. Terok Nor: Dawn of the Eagles
  4. Fallen Heroes
  5. The Long Night
  6. The 34th Rule
  7. Tales of the Dominion War
  8. Hollow Men
  9. Prophecy and Change
  10. The Lives of Dax
  11. The Left Hand of Destiny, Book One
  12. The Left Hand of Destiny, Book Two
  13. A Stitch in Time
  14. Avatar, Book One
  15. Avatar, Book Two
  16. Section 31: Abyss
  17. Gateways: Demons of Air and Darkness
  18. Mission: Gamma- Twilight
  19. Mission: Gamma- This Gray Spirit
  20. Mission: Gamma- Cathedral
  21. Mission: Gamma- Lesser Evil
  22. Rising Son
  23. Unity
  24. Worlds of Deep Space Nine: Volume One
  25. Worlds of Deep Space Nine: Volume Two
  26. Worlds of Deep Space Nine: Volume Three
  27. Warpath
  28. Fearful Symmetry
  29. The Soul Key
  30. The Never-Ending Sacrifice

Thirty Novel Version
(With Focus on the Post-Finale Era)

  1. The Lives of Dax
  2. The Left Hand of Destiny, Book One
  3. The Left Hand of Destiny, Book Two
  4. A Stitch in Time
  5. Avatar, Book One
  6. Avatar, Book Two
  7. Section 31: Abyss
  8. Gateways: Demons of Air and Darkness
  9. Mission: Gamma- Twilight
  10. Mission: Gamma- This Gray Spirit
  11. Mission: Gamma- Cathedral
  12. Mission: Gamma- Lesser Evil
  13. Rising Son
  14. Unity
  15. Worlds of Deep Space Nine: Volume One
  16. Worlds of Deep Space Nine: Volume Two
  17. Worlds of Deep Space Nine: Volume Three
  18. Warpath
  19. Fearful Symmetry
  20. The Soul Key
  21. Typhon Pact: Rough Beasts of Empire
  22. Typhon Pact: Zero Sum Game
  23. Typhon Pact: Plagues of Night
  24. Typhon Pact: Raise the Dawn
  25. The Fall: Revelation and Dust
  26. Sacraments of Fire
  27. Ascendance
  28. Coda: Moments Asunder
  29. Coda: The Ashes of Tomorrow
  30. Coda: Oblivion's Gate


Forty Novel Version
(With Focus on the Series Era)

  1. Terok Nor: Day of the Vipers
  2. Terok Nor: Night of the Wolves
  3. Terok Nor: Dawn of the Eagles
  4. The Siege
  5. Fallen Heroes
  6. Devil in the Sky
  7. The Long Night
  8. The 34th Rule
  9. Tales of the Dominion War
  10. Hollow Men
  11. Millennium: The Fall of Terok Nor
  12. Millennium: The War of the Prophets
  13. Millennium: Inferno
  14. The Next Generation: The Battle of Betazed
  15. Prophecy and Change
  16. The Lives of Dax
  17. The Left Hand of Destiny, Book One
  18. The Left Hand of Destiny, Book Two
  19. A Stitch in Time
  20. Avatar, Book One
  21. Avatar, Book Two
  22. Section 31: Abyss
  23. Gateways: Demons of Air and Darkness
  24. Mission: Gamma- Twilight
  25. Mission: Gamma- This Gray Spirit
  26. Mission: Gamma- Cathedral
  27. Mission: Gamma- Lesser Evil
  28. Rising Son
  29. Unity
  30. Worlds of Deep Space Nine: Volume One
  31. Worlds of Deep Space Nine: Volume Two
  32. Worlds of Deep Space Nine: Volume Three
  33. Warpath
  34. Fearful Symmetry
  35. The Soul Key
  36. The Never-Ending Sacrifice
  37. Typhon Pact: Rough Beasts of Empire
  38. Typhon Pact: Zero Sum Game
  39. Typhon Pact: Plagues of Night
  40. Typhon Pact: Raise the Dawn

Forty Novel Version
(With Focus on the Post-Finale Era)

  1. The Lives of Dax
  2. The Left Hand of Destiny, Book One
  3. The Left Hand of Destiny, Book Two
  4. A Stitch in Time
  5. Avatar, Book One
  6. Avatar, Book Two
  7. Section 31: Abyss
  8. Gateways: Demons of Air and Darkness
  9. Mission: Gamma- Twilight
  10. Mission: Gamma- This Gray Spirit
  11. Mission: Gamma- Cathedral
  12. Mission: Gamma- Lesser Evil
  13. Rising Son
  14. Unity
  15. Worlds of Deep Space Nine: Volume One
  16. Worlds of Deep Space Nine: Volume Two
  17. Worlds of Deep Space Nine: Volume Three
  18. Warpath
  19. Fearful Symmetry
  20. The Soul Key
  21. Destiny: Gods of Night
  22. Destiny: Mere Mortals
  23. Destiny: Lost Souls
  24. Typhon Pact: Rough Beasts of Empire
  25. Typhon Pact: Zero Sum Game
  26. Typhon Pact: Paths of Disharmony
  27. Typhon Pact: Plagues of Night
  28. Typhon Pact: Raise the Dawn
  29. The Fall: Revelation and Dust
  30. The Fall: The Crimson Shadow
  31. The Fall: A Ceremony of Losses
  32. The Fall: The Poisoned Chalice
  33. The Fall: Peaceable Kingdoms
  34. Sacraments of Fire
  35. Ascendance
  36. Section 31: Disavowed
  37. Section 31: Control
  38. Coda: Moments Asunder
  39. Coda: The Ashes of Tomorrow
  40. Coda: Oblivion's Gate

Fifty Novel Version
(With Focus on the Series Era)

  1. Terok Nor: Day of the Vipers
  2. Terok Nor: Night of the Wolves
  3. Terok Nor: Dawn of the Eagles
  4. The Siege
  5. Fallen Heroes
  6. Devil in the Sky
  7. The Long Night
  8. The Heart of the Warrior
  9. The 34th Rule
  10. Tales of the Dominion War
  11. Hollow Men
  12. Millennium: The Fall of Terok Nor
  13. Millennium: The War of the Prophets
  14. Millennium: Inferno
  15. The Next Generation: The Battle of Betazed
  16. Prophecy and Change
  17. The Lives of Dax
  18. The Left Hand of Destiny, Book One
  19. The Left Hand of Destiny, Book Two
  20. A Stitch in Time
  21. Avatar, Book One
  22. Avatar, Book Two
  23. Section 31: Abyss
  24. Gateways: Demons of Air and Darkness
  25. Mission: Gamma- Twilight
  26. Mission: Gamma- This Gray Spirit
  27. Mission: Gamma- Cathedral
  28. Mission: Gamma- Lesser Evil
  29. Rising Son
  30. Unity
  31. Worlds of Deep Space Nine: Volume One
  32. Worlds of Deep Space Nine: Volume Two
  33. Worlds of Deep Space Nine: Volume Three
  34. Warpath
  35. Fearful Symmetry
  36. The Soul Key
  37. The Never-Ending Sacrifice
  38. Typhon Pact: Rough Beasts of Empire
  39. Typhon Pact: Zero Sum Game
  40. Typhon Pact: Plagues of Night
  41. Typhon Pact: Raise the Dawn
  42. The Fall: Revelation and Dust
  43. The Fall: A Ceremony of Losses
  44. Sacraments of Fire
  45. Ascendance
  46. Section 31: Disavowed
  47. Section 31: Control
  48. Coda: Moments Asunder
  49. Coda: The Ashes of Tomorrow
  50. Coda: Oblivion's Gate

Fifty Novel Version
(With Focus on the Post-Finale Era)

  1. The Lives of Dax
  2. The Left Hand of Destiny, Book One
  3. The Left Hand of Destiny, Book Two
  4. A Stitch in Time
  5. Avatar, Book One
  6. Avatar, Book Two
  7. Section 31: Abyss
  8. Gateways: Demons of Air and Darkness
  9. Mission: Gamma- Twilight
  10. Mission: Gamma- This Gray Spirit
  11. Mission: Gamma- Cathedral
  12. Mission: Gamma- Lesser Evil
  13. Rising Son
  14. Unity
  15. Worlds of Deep Space Nine: Volume One
  16. Worlds of Deep Space Nine: Volume Two
  17. Worlds of Deep Space Nine: Volume Three
  18. Warpath
  19. Fearful Symmetry
  20. The Soul Key
  21. The Never-Ending Sacrifice
  22. Destiny: Gods of Night
  23. Destiny: Mere Mortals
  24. Destiny: Lost Souls
  25. A Singular Destiny
  26. D.T.I.: Watching the Clock
  27. Typhon Pact: Rough Beasts of Empire
  28. Typhon Pact: Zero Sum Game
  29. Typhon Pact: Paths of Disharmony
  30. Typhon Pact: Plagues of Night
  31. Typhon Pact: Raise the Dawn
  32. Typhon Pact: Brinkmanship
  33. The Fall: Revelation and Dust
  34. The Fall: The Crimson Shadow
  35. The Fall: A Ceremony of Losses
  36. The Fall: The Poisoned Chalice
  37. The Fall: Peaceable Kingdoms
  38. Lust's Latinum Lost (and Found)
  39. The Missing
  40. Sacraments of Fire
  41. Ascendance
  42. Force and Motion
  43. Section 31: Disavowed
  44. The Long Mirage
  45. Gamma: Original Sin
  46. Section 31: Control
  47. Enigma Tales
  48. Coda: Moments Asunder
  49. Coda: The Ashes of Tomorrow
  50. Coda: Oblivion's Gate