Sometime in the fall of 1990, my parents gave me a Nintendo Entertainment System Action Set: a grey, boxy Control Deck, two controllers, a bright orange "Zapper" light gun, and a cartridge that contained both Super Mario Bros. and Duck Hunt. ⊕
An NES console with one controller.
Photo by Evan Amos. The Control Deck plugged into the big CRT TV we had in the basement via an RF switch, basically an antenna that fed video from the Control Deck to the TV when you tuned it to Channel 3. It was the first video game console we had ever owned, and I loved it.

I spent a lot of time in the basement that year. At first, my dad did too - he was working his way through Super Mario Bros., learning where the secret Warp Zones were located and how to get past the menacing Hammer Bros. Eventually he defeated Bowser (or “the dragon”, as he called him), saved the princess, and never really played an NES game ever again.

I was hooked, though. We got a promotional letter in the mail offering a free copy of Dragon Warrior for subscribing to Nintendo Power magazine; signing up for a $20 magazine subscription to get a $50 game was a no-brainer.⊕
Dragon Warrior (US box art). Dragon Warrior introduced me to RPGs in the same way that Super Mario Bros. had introduced me to platformers. There were plenty of other games that I spent time with, too: Ducktales, Final Fantasy, Contra, and Mega Man III were some of my favorites.

The NES ultimately set me on a career path. As a kid, I knew that video games were special, and that making video games was what I wanted to do as an adult. I had the (mistaken) belief that a career making video games meant a career playing video games. I started learning C++ once my family got a computer because that was what “real” programmers used. (Little did I know that NES programmers don't use C++, but in my defense I was young and naive.) I never made any actual games, though. Game programming always seemed more complicated than I was prepared for, and besides, there was no shortage of great games from other people waiting to be played.

That dream stuck with me, and after years of being a professional web developer I started learning NES development. (I got a strong nudge in the right direction from Nathan Altice’s excellent I Am Error.)⊕
I Am Error. It was hard to know where to begin. There were plenty of resources around the internet, but they were all incomplete or inaccurate in some way. I got started with bunnyboy's "Nerdy Nights" series on the NintendoAge forums. Then I found tepples' NROM template on GitHub, and started learning the ca65 assembler. After months of struggling to understand PPU writes, attribute tables, and scroll registers, it all started to click. I'm glad that I had the experience of fighting with these concepts to learn on my own, but I wish that I could have had a guide that started from scratch and taught all of the essentials of NES development.

My hope is that the book you are now reading will serve as that guide.