Crucial Conversations
Primal Leadership
It's Your Ship
For negotiating there are a couple that espouse different tactics for different situations
Getting to Yes - for maintaining relationships
The Power of No - for getting the best deal in one-offs
As a doctor in training, you're going to see a lot of less effective leadership styles. We are trained to find faults - in patients, in ourselves, in our teammates. Outside of academia, the job is significantly less hierarchical and we typically underappreciate and under recognize the contributions of our staff. If you get in the habit of genuinely recognizing someone you work with every shift, you'd be amazed what it does for your work environment.