Tony Hsieh, the late former CEO of Zappos, wrote the definitive playbook on corporate culture. Here are 4 lessons from his bestseller 'Delivering Happiness.'

• Tony Hsieh, the former leader of online retail giant Zappos, died suddenly on November 27.
• He is credited with influencing how businesses approach company culture and customer service, pioneering a philosophy of happiness above profits.
• That philosophy is laid out in his 2010 best-seller "Delivering Happiness: A Path to Profits, Passion, and Purpose."
• The book remains highly influential a decade on. Scroll on to read four key lessons from Hsieh's work.

Tributes continue to pour in for Tony Hsieh, the entrepreneur famed for building online shoe and clothing giant Zappos.

Hsieh died on November 27 due to injuries he sustained from a house fire in Connecticut. He was 46 years old.

Tributes came from those who had not only met Hsieh but had read his highly influential first book "Delivering Happiness."

The entrepreneur was widely credited for raising the bar for customer service in online retail, laying out his philosophy around happiness in the 2010 book. Hsieh and his cofounder Alfred Lin famously maintained a focus on Zappos' culture after its sale to Amazon in 2009.

The book was number one on the New Your Times Best Seller List the year of its release and it remains Amazon's number one bestseller in the law for small businesses section and number four in the site's entrepreneurship category.

Hsieh's lessons evidently still hold true a decade on. Here are four key lessons from the book:

1. Find your one true passion and don't follow the money

It's important to figure out the one thing you're passionate about, Hsieh wrote. If you have that in mind and know what your ultimate goal is, subsequent decisions will become easier to make.

"You want to figure out the right balance of profits, passion, and purpose in business and in life," Hsieh wrote.

During his first couple of years at Zappos, Hsieh and his cofounder Alfred Lin struggled to make a profit and had only a couple of months' worth of cash.

Coming from their successful prior business, LinkExchange, they thought it would have been easy to raise new funds until it wasn't. They halted thinking solely about profit, were clear with their staff about the economic situation, cut jobs and salaries, and worked with the remaining of the team to find solutions to make the business profitable.

The remaining team stepped up and worked harder than before. The layoffs didn't hurt the company's productivity due to the staff's effort but also because they were passionate about the company, and believed in its future and potential.

"It was a big lesson in the power of instilling passion throughout the entire company and working as a unified team. Everyone was making sacrifices," Hsieh wrote.

Hsieh wanted to transform Zappos from a good to a great company: "Great companies have a greater purpose and bigger vision beyond just making money or being number one in a market," wrote Hsieh, citing the book "Good to Great" by Jim Collins. "A lot of companies fall into the trap of just focusing on making money, and then they never become a great company."

2. Hire the right people, have the right company culture, and the rest will develop

Treat people well and only hire people you would hang out with outside of working hours. "Many of the best ideas came about while having drinks at a local bar," said Hsieh. Those are the people who will make you want to go to work and feel part of a bigger family — the ''friends of Zappos" in Hsieh's case — and therefore do whatever needed to make a company successful.

You also need to actively foster culture. "You want to create a stronger company culture, which will make your employees and coworkers happier and create more employee engagement, leading to higher productivity," Hsieh wrote.

Culture was famously a major priority for Hsieh, who saw this as key to the success of the business. He asked all his staff to write down what the business meant to them, and made a book out of their thoughts — none being censored. Every year a new edition would be produced, with new sentences added and changed. Hsieh would give out that new version of the Zappos Culture Book to prospective employees, vendors, and even customers.

3. Surprise your customers and show them how much you care

In 2003, the dot-com crash was still hammering Zappos' profit.

Hsieh decided to make customer service the focus of the business. He wrote that at the time it felt like the only choice for its survival but realized later on it was actually "a blessing in disguise."

Good customer service builds a brand and drives word of mouth, he said.

"Our philosophy has been to take most of the money we would have spent on paid advertising and invest it into customer service and the customer experience instead, letting our customers do the marketing for us through word of mouth," Hsieh wrote.

That involved measuring whether Zappos employees went "above and beyond" for customers, rather than measuring them on call volumes.

Another way was to continually "wow" customers — for example giving loyal customers overnight shipping even when they only promised the standard option.

4. Make learning a priority for yourself and staff

Hsieh called himself an "avid book reader" and made a compulsory book list for his staff. Zappos' office had a library with thousands of books and offered courses on the most important titles.

Continual growth should always be any business's priority, the entrepreneur wrote. And any workplace should appreciate employees spending time and effort into their personal and professional development, allowing them to take up challenges as soon as they are ready.