Books like Lady Knightley's Secret
Anne Ashley
Lady Knightley's Secret is 300 pages, about 5 hours 30 minutes at 250 words a minute.
12 books to read next
How long each takes
Regency Buck 6.4 h 
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More Than a Mistress / No Man's Mistress 6.6 h 
An Infamous Army 8.0 h 
Arabella 5.8 h 
Because of Miss Bridgerton 5.6 h 
A Civil Contract 7.2 h 
Cousin Kate 5.9 h 
The Woman in White 10.0 h 
The Viscount Who Loved Me 7.3 h 
Sprig Muslin 5.3 h 
Persuasion 4.9 h Bar height shows length. Estimated at 250 words a minute.