What Was the Inspiration for on Liberty?

In 1859, he publishes on liberty. What was the inspiration for his writing it? As you state, it was kind of different than things he had written before. Well, he and Harriet together thought that in one letter, Mill actually describes on liberty and some other things as a kind of mental pymican,. I think I'm pronouncing that correctly. The kind of dried meat and berries that Native Americans might have used as sort of survival food.