"Never Split the Difference" by Chris Voss offers invaluable negotiation techniques derived from high-stakes hostage negotiations. The book emphasizes the importance of empathetic communication, strategic use of 'no' to gain advantage, and the power of calibrated questions to uncover hidden needs, all of which can transform tech negotiations and deal-making. 

"The Mom Test" by Rob Fitzpatrick is a crucial guide for entrepreneurs and product developers in the tech world, focusing on how to conduct meaningful customer interviews. The book challenges conventional customer feedback methods, emphasizing the need to focus on customers' behavior and problems rather than their opinions on an idea or product.