Buying, or selling, a business is a complex and, trust me, pretty emotional process. Those books should help you find some guidance in an M&A process: Winning at the Acquisition Games gives a practical overview of activities to accomplish before, during, and after a deal. It describes concepts like the Letter of Intent (LOI), the Stock Purchase Agreement (SPA) and Reps and Warranties. The Intelligent Exit is one of the only book focused on the seller perspective: quite refreshing if you are looking to sell your business. Finally, Valuation from McKinsey & Company is a classic on the technical aspect of business valuation.