Book excerpt: Silicon Valley is full of start-up success stories; every day stories emerge of a new company with the potential for a billion-dollar valuation and plans for global domination. But what can we really learn from these stories? How many of these start-ups are genuinely successful in the long term? When nine out of ten start-ups end in spectacular burnout, how can we ensure our own success story? While most books and press focus on the more sensational moments of creation and conclusion, The Messy Middle argues that the real key to success is how you navigate the ups-and-downs after initial investment is secured. It will give you all the insights you need to build and optimize your team, improve your product and develop your own capacity to lead. Building on seven years' of meticulous research with entrepreneurs, small agencies, start-ups and billion-dollar companies, Scott Belsky offers indispensable lessons on how to endure and thrive in the long term.