Growing up, we called moments of inspiration times when ‘the light bulb went off’ in our heads. Those were the times you could see exactly what needed to be done to solve the challenge at hand. These days, we still look to ‘a-ha moments’ to give us answers. But what if an a-ha moment changed not only the course of your life, but those of scores of employees and the future of a business, as well?

Every day in corner offices around the world, they do. Some involve big investments. Others are fueled by leaps of faith. A few are based on good old-fashioned instinct. In the end they all demand one thing: tough calls from the corner office.

Harlan Steinbaum’s new book by the same name is a collection of these life- and career-defining moments by some of the greatest business men and women of our time. Inside its pages are insights from Wellpoint’s Angela Braly, ESPN’s Bill Rasmussen, Time Inc.’s Reginald Brack and Verizon’s Frederic Salerno, just to name a few. Steinbaum, a St. Louis author, served as CEO of Medicare-Glaser and as chairman of Express Scripts. The idea to delve into the a-ha decisions of others came to him after looking back at his own career-defining moment of buying back his family’s business. The result of his work is a great read full of tough calls that are not only interesting, but also enlightening.

Steinbaum’s connection with St. Louis’ business community also allowed him a look inside the heads of many of local leaders and innovators. Tough Calls groups executives’ stories into chapters that expand avenues of leadership. There are accounts from Build-A-Bear’s Maxine Clark and World Wide Technology’s David Steward on trusting instincts and having faith when stepping out to be an entrepreneur. A.G. Edwards’ Benjamin Edwards and McDonnell Douglas’ Sanford McDonnell share what it takes to change corporate culture when the status quo is obstructing success; while refocusing and renewing a business are subjects tackled by Monsanto’s Richard Mahoney and Panera’s Ronald Shaich.

One of my favorite stories from the book actually took place in a TV studio with Let’s Make a Deal’s Monty Hall, who worked doggedly early in his career and created the most successful game show in television history. The trouble was in Monty’s ‘deal’ with ABC: It gave the network most of the winnings from his popular program. Monty’s tough call came in continuing with his career ‘as-is’ or taking a stand to make it better. He turned his back on the money in-pocket and went for what was behind Door No. 2.

Some of the greatest lessons garnered from the book are those discovered by the author himself while compiling the stories. Overwhelmingly and across all industries, these executives succeeded because they either: followed their passion (like Angela Braly giving up law for a career in health care), realized that ethical business behavior also made for a smart business practice (like Reg Black’s reign at Time where the author writes that Black challenged the ‘good old boy network’), or never shied away from risk (like Fleishman-Hillard’s John Graham who personally financed his company’s national and international growth)—or all of the above.

While working as a CEO and chairman, the author says he always felt the right attitude for any leader was to “be humble in success and open in failure.” Inside his book, he shares both triumphs and losses through unprecedented stories by and about those leaders who have built a lifetime of character from the decision of one moment. They’ve taken ownership of those moments and now, we can all learn lessons from some pretty tough calls made by some outstanding leaders.

Benjamin Ola. Akande is Dean of the George Herbert Walker School of Business and Technology and chief of corporate partnerships at Webster University. Follow him on Twitter: @Benjamin_Akande