MBA lessons by Fred Wilson

Great source of (free!) knowledge regarding all things related to business in general, but more specifically for tech start-up companies:

MBA Mondays Illustrated

• Legal & Finance 101
• Accounting
• Building a company
• Economics & Finance
• Operations
• Employee equity
• Mergers & Acquisitions
• M&A case studies
• M&A issues
• Operations, finance etc.
• Financing options
• Venture investing
• The management team
• The board of directors

MBA Mondays was originally a series of "business 101" articles written by noted venture capitalist Fred Wilson that ran between 2010 and 2013. Wilson is a highly regarded and very successful Venture Capitalist from New York.