If you have ever considered starting your own business, or maybe you are at the beginning stages of your startup, you owe it to yourself to read the book The Purpose Is Profit: The Truth about Starting and Building Your Own Business by Ed "Skip" McLaughlin and Wyn Lydecker. The book is very complete and covers everything from the type of business you should start to the important factors in selling your business.
Some of the more important chapters are Dynamic Planning which covers realization of the business vision in spite of and dealing with challenges, Entrepreneurial Branding, Sales is a Contact Sport, and Realizing Value.
One of the more important lessons covered in the book is that it is better to bootstrap than use other people's money. Another lesson is that profit should be examined for every decision that is made.
The section I found most informative was Appendix B: The Startup Funding Guide, which spells out how to determine how much funding you need, forecasting, valuation, and sources of funding.
For all you starters out there, I highly recommend The Purpose Is Profit.