How to Win Friends and Influence People in the Digital Age

by Dale Carnegie (paid link)

How to Have Confidence and Power in Dealing with People

by Les Giblin (paid link)

How to Stop Worrying and Start Living

by Dale Carnegie (paid link)

Boundaries: When to Say Yes, How to Say No To Take Control of Your Life

by Henry Cloud & John Townsend (paid link)

Pitch Anything: An Innovative Method for Presenting, Persuading, and Winning the Deal

by Oren Klaff (paid link)

Start with Why: How Great Leaders Inspire Everyone to Take Action

by Simon Sinek (paid link)

StrengthsFinder 2.0

by Tom Rath (paid link)

The Lean Startup

by Eric Ries (paid link)