It's an important question. The reality is that your company already has a culture, but it might not be acknowledged or actively managed. In addition to reading these books, you can take an honest look at who you comprises your organization, what you aspire to accomplish together, and why you're doing it. What are the shared values and connective tissues of the team? There can be a big divide between what a company thinks its culture is and what it actually is...The hardest part, especially at startups, is that cultural outcasts must be removed.