I was Peter. Fresh out of university with degrees in Applied Mathematics and Software Engineering, I could solve algorithms but couldn't explain why production systems worked the way they did. "Idempotency"? Googled it secretly. "Stateless design"? Nodded along, panicked inside. The imposter syndrome was real. Then patient senior developers sat down and explained what bootcamps skip and universities gloss over. Those conversations changed everything. They transformed confusion into confidence, anxiety into understanding. Now, as a senior engineer, I've had those same conversations with dozens of struggling juniors. I saw the same questions, the same relief when concepts finally clicked. This book is those conversations. For every Peter who feels lost. For every developer who deserves answers, not gatekeeping.