There are 22 books by Isabel Ostrander on BookOrb. A strong starting point is The twenty-six clues (1919). The bibliography below is in publication order, with series grouped in reading order.
Biography
Standalone books
Frequently asked questions
How many books has Isabel Ostrander written?
BookOrb lists 22 books by Isabel Ostrander.
Where should I start with Isabel Ostrander?
A good starting point is The twenty-six clues (1919).
What is the Isabel Ostrander books in order list?
In publication order: 1. At one-thirty (1915), 2. The primal law (1915), 3. The clue in the air (1917), 4. Island of intrigue (1918), 5. The twenty-six clues (1919), 6. The single track (1919), 7. How many cards? (1920), 8. The man who convicted himself (1920), 9. The trigger of conscience (1921), 10. The crimson blotter (1921), 11. The tattooed arm (1922), 12. Two-gun Sue (1922), 13. The neglected clue (1925), 14. The black joker (1925), 15. The sleeping cat (1926), and 7 more.