If you’re holding this book, I’m going to assume one of three things. One, you’re genuinely curious about the wild world of bodily functions and not afraid to laugh about it. Two, you’ve had a recent “incident” and need answers. Or three, you just like the word shart and wanted to see where this was going. No judgment. All of the above is perfectly reasonable.

Now, let’s get something straight right outta the chute. I am not a doctor. I am not a scientist. I’m just a woman with a long history of bowel-related mishaps, a love for sciencey rabbit holes, and zero shame about saying words like poop and fart out loud in public. My name’s Kate Baxter, and I am here to guide you on a deeply intimate, slightly horrifying, extremely educational journey into the mysterious underworld of human digestion, flatulence, and yes, the occasional pants betrayal.

I grew up in a household where farting was an Olympic sport. My brothers were the ringleaders, my dad was the referee, and my mom just tried to survive. We weren’t a family that whispered about bodily functions. We were the kind that gave our farts names and backstories. Like, I remember once blaming a particularly vicious stinker on the dog, only for my cousin to shout, “Don’t blame that on Daisy, Kate, I saw your eyes water when it came out.” Family is about honesty, y’all.

But here’s the thing. Even if you didn’t grow up in a gastrointestinal comedy club like I did, you still fart. You still poop. And unless you are some kind of mythical unicorn, you’ve probably had a moment when you gambled on a toot and lost everything. That, my friend, is the essence of the shart. It is the great equalizer. It brings us together across time, culture, age, and dignity. Everybody poops, sure, but not everybody talks about it. I do. I will. Right here in this book.

What started as a few unfortunate incidents in my twenties turned into a deep fascination with what’s actually happening in our guts. Why does one day’s poop feel like a satisfying exorcism and the next day’s like a cry for help? Why do some farts sneak out like ninjas and others sound like they’re announcing their presence with a trumpet and full marching band? What’s the science behind those bowel movements that feel like a religious experience versus the ones that feel like betrayal?

This book is your field guide to the wild, squelchy, gassy frontier of your own behind. We’re going to explore the biology, the mechanics, the chemistry, and the glorious unpredictability of the human digestive system. I’ll share stories that should probably embarrass me but don’t because, frankly, I’ve already cried in public bathrooms and farted on first dates. There’s nothing left to lose.

So buckle in, stock up on fiber, and keep a spare pair of underwear handy just in case. This is Shart Science 101 and class is officially in session.