I was an extremely lucky kid. I was born to great parents who did everything to set me up for success. I grew up in a city I love and still call home, at the dawn of the computer age. And I went to one of two schools in my state—one of a handful in the country—that actually had computer access. These were all strokes of luck that helped shape my future.

But equally important, maybe most important, were the teachers I was fortunate enough to learn from along the way. In my new book, Source Code, I write about many of them. From grade school through college, I had teachers who saw my potential (even when it was buried under bad behavior), gave me real responsibilities, let me learn through experience instead of lectures, and created space for me to explore my passions.

These five brilliant teachers didn’t just teach me subjects; they taught me how to think about the world and what I might accomplish in it. Looking back, I realize how rare this was—and how lucky I was to find it over and over again. 

Blanche Caffiere

Blanche Caffiere entered my life twice—first as my first-grade teacher, and later as my first “boss,” when I was in fourth grade at View Ridge Elementary and she was the librarian. At the time, I was a handful in (and out of) class: energetic, disruptive, constantly lost in my own thoughts. Most teachers and administrators saw me as a problem to be solved. But Mrs. Caffiere saw a problem-solver in me instead. When one of my teachers struggled with how to challenge me and channel my energy, she stepped in and gave me a job as her library assistant. 

“What you need is kind of like a detective,” I said when she tasked me with finding missing books that were lost somewhere in the library. I warmed to the work immediately, roaming the stacks until I found each one. Then Mrs. Caffiere taught me the Dewey Decimal system by having me memorize a clever story about a caveman, so I could figure out where each book belonged. For a kid who loved reading and numbers, it was a dream job. I felt essential. I stayed through recess that first day, showed up early the next morning, and ended up working in the library for the rest of the year.

When my family moved and I had to leave View Ridge Elementary, I was most devastated about leaving my library job. “Who will find the lost books?” I asked. Mrs. Caffiere responded that I could be a library assistant at my new school. She understood that what I needed wasn’t just busy work, but a sense of being valued and trusted with real responsibility. She’d been teaching for nearly forty years when we met, which meant she’d seen every kind of student imaginable. But she had a particular gift for helping those at the extremes—the ones who were struggling or excelling—find their way. I was a little of both, and she certainly helped me find mine.

Paul Stocklin

Paul Stocklin’s eighth-grade math class at Lakeside changed my life in two profound ways, though I couldn’t have known it at the time. First, it was where I met Kent Evans, who would become my best friend and earliest “business” partner before his tragic death in a mountain climbing accident at age 17. Like me, Kent didn’t easily fit into the established cliques at Lakeside. Unlike me, he had a clear vision for his future, which inspired me to start thinking about my own.

It was also in Mr. Stocklin’s class that I first saw a teletype machine—an encounter that would shape my entire future. One morning, Mr. Stocklin led our class down a hall in McAllister House, a white clapboard building at Lakeside that was home to the school’s math department, where we heard an unusual “chug-chug-chug” sound echoing from inside a room. There, we saw something that looked like a typewriter with a rotary telephone dial. Mr. Stocklin explained that it was a teletype machine connected to a computer in California. With it, we could play games and even write our own computer programs—something I’d never thought I’d be able to do myself. That moment opened up a whole new world for me.

There’s a lot more I’ve come to appreciate about Mr. Stocklin, including how much he encouraged an early love of math in me. But it’s undeniable that he changed my life by facilitating two of the most important relationships of my early years: my friendship with Kent, and my introduction to computing. These were gifts from him that I’ll appreciate forever, even though one would end in heartbreak.

Bill Dougall

Bill Dougall embodied what made Lakeside special—he was a World War II Navy pilot and Boeing engineer who brought real-world experience to teaching. Beyond his degrees in engineering and education, he had even studied French literature at the Sorbonne. He was the kind of Renaissance man who took sabbaticals to build windmills in Kathmandu.

As head of Lakeside’s math department, Mr. Dougall was instrumental in bringing computer access to our school, something he and other faculty members pushed for after taking a summer computer class. Even though it was expensive—over $1,000 a year for the terminal and thousands more in computer time—he helped convince the Mothers’ Club to use the proceeds from their annual rummage sale to lease a Teletype ASR-33.

The fascinating thing about Mr. Dougall was that he didn’t actually know much about programming; he exhausted his knowledge within a week. But he had the vision to know it was important and the trust to let us students figure it out. His famous camping trips, a sacred tradition at Lakeside, showed another side of his belief in experiential learning. These treks took students through whatever weather the Pacific Northwest could throw at forty boys and a few intrepid teachers. They taught resilience, teamwork, and problem-solving in a way that no classroom ever could. That was the essence of Mr. Dougall’s teaching philosophy.

Fred Wright

Fred Wright was exactly the kind of teacher we needed in the computer room at Lakeside. He had no practical computer experience, though he’d studied the FORTRAN programming language. But he was relatively young (in his late twenties) and only recently hired, and he intuitively understood that the best way to get students to learn was to let us explore on our own terms. There was no sign-up sheet, no locked door, no formal instruction.  

Instead, Mr. Wright let us figure things out ourselves and trusted that, without his guidance, we’d have to get creative. At some point, a student taped a sign above the door that said “Beware of the Wrath of Fred Wright”—a tongue-in-cheek nod to his laissez-faire oversight of the computer room. Some of the other teachers argued for tighter regulations, worried about what we might be doing in there unsupervised. But even though Mr. Wright occasionally popped in to break up a squabble or listen as someone explained their latest program, for the most part he defended our autonomy.

Officially, he was the adult sponsor of our work at Lakeside. Unofficially, Mr. Wright gave us something invaluable: the space to discover our own potential. That was also his approach to geometry class, where I was his student in tenth grade. I remember him watching with amusement as I powered through problems using algebra instead of geometry. Rather than force me to do it the right way, he let me forge my own path, knowing I’d eventually figure out the more efficient (geometric) solution. 

Daniel Morris 

Dr. Daniel Morris was different from most high school science teachers. With a PhD from Yale and a patent for isolating tryptophan, he was a former industrial chemist who brought real-world expertise to our chemistry classroom. Some might have found it pretentious that he wore a lab coat and drank coffee from a glass beaker, but he earned those rights. I think he also earned the label that I’ve long used to describe him: the world’s greatest chemistry teacher. 

What made Dr. Morris so memorable was his ability to transform the rote memorization that most people associate with chemistry into unifying concepts that explain the world around us. He demystified complex processes by using everyday examples—to teach, for example, why soda stays fizzy if you put the cap back on, or what makes super glue that sticky. The introduction he wrote to his own chemistry textbook captures his teaching style perfectly: “We seem to forget the true foundation stone of science: the belief that the world makes sense.”

Before him, the sciences were subjects I did well in analytically but didn’t much care to practically understand or apply. That wasn’t good enough for Dr. Morris, who gave me a hard time for just getting by with what I already knew. Instead, he forced me into the lab to do experiments; to this day, I trace my love of science back to the demands he put on me to really get chemistry. He’s the reason I decided to take organic chemistry at Harvard—even though the class was mostly pre-med students, and I had no plans to become a doctor. (I got a C, my lowest grade in college, but I don’t think I ever told him.)

Tom Cheatham 

Looking back on my time at Harvard, I’m grateful for Professor Tom Cheatham’s hands-off approach to some of the most hands-on learning I’ve ever done. As director of the Aiken Computation Lab, he made an extraordinary exception by granting me access to the school’s PDP-10 computer—a privilege typically reserved for graduate students and other professors. Back then, Harvard didn’t even have an undergraduate computer science major.  

When we first met, I was an overconfident freshman, practically jumping out of my chair as I pitched him on all my ideas; I remember him taking drags on his Parliament cigarettes as I spoke, seeming pretty uninterested. I later learned that administrative tasks—signing students’ study cards and managing the day-to-day of the lab—were Cheatham’s least favorite parts of his job. Having come to Harvard after years working in industry and government, he was a programmer at heart, designing new computer languages when he wasn’t off meeting with the Department of Defense and securing more funding for the lab.

But he must have seen (and liked) something in me—either my technical experience, my teenage enthusiasm, or both. In my sophomore year, he made another exception and agreed to be my advisor for an engineering independent study to write a computerized baseball game. While I regret that we never formed a closer relationship, Cheatham was clearly in my corner. I knew that then and was reminded of it again recently, when I saw my old college records and learned how he’d defended me when I got in trouble for bringing friends into the lab without permission: It would be a “travesty of justice” if I were forced to withdraw from Harvard, Cheatham told the university’s Administrative Board, adding that he “would be delighted to have BG computing at the Center next year.”

I don’t think I ever properly thanked any of my teachers, including Professor Cheatham, for seeing something in me that I didn’t always see in myself. So many of them passed away before I had the chance. But I am who I am today because of their influence. So in Source Code, I’m sharing their stories and giving credit where it’s due. After all, one brilliant teacher, one mind-blowing class, is enough to change a person’s life. I’m so lucky and grateful to have had many.