Mindset and leadership (explore other titles by Gerald M. Weinberg as well)

- An Introduction to General Systems Thinking

- Becoming a Technical Leader: An Organic Problem-Solving Approach

So that you have a good answer to "when will it be ready"

- Software Estimation: Demystifying the Black Art

- Agile Estimating and Planning

People management

- The Manager's Path: A Guide for Tech Leaders Navigating Growth and Change

- High Output Management

Besides Mythical Man Month already mentioned in other comments.