Recent quotes:

How Getting Canceled on Social Media Can Derail a Book Deal - The New York Times

The clauses vary from publisher to publisher, and even from one literary agency to the next — every agency strikes its own deal with each publishing house — but the general principle is that they take aim at conduct that would invite widespread public condemnation or significantly diminish sales among the book’s intended audience, and that the publisher didn’t previously know about when it signed the deal. If an author has a propensity for getting in fistfights, for example, the book cannot be dropped because he or she gets in another one.