If we were to believe the tale, the Lernean Hydra was a veritable horror show of fangs and fury. Nine heads sat atop its massive serpentine body. Breathing poison and snapping jaws, the hydra’s heads would work in unison to simultaneously attack and defend against any would-be champions. Towering above any mortal, the mythological beast lived in isolation, because only the truly foolish would venture out and try to tame it.

When Hercules fought the hydra in the brackish swamps near Lake Lerna, the Greek hero had a few advantages (see Figure I-1). Though mortal, Hercules was favored by the gods. He had already defeated the ferocious, fabled Nemean lion and wore its impenetrable pelt like a suit of armor. Along with his legendary strength, Hercules was well on his way to BCE stardom. He had fought giants, mercenaries, and a virtual pan-Hellenic petting zoo full of other creatures. But the hydra was different. For each time Hercules would cut off one of its heads, two heads would grow back in replacement.

Hercules would come to defeat the hydra by tackling one head at a time. He and his trusty assistant would lop off a head, cauterize the respective wound, and repeat the process until the job was done.

Defining UX principles can be a bit like battling a hydra. You tackle one principle, wait a short while, and two or more additional principles pop up in its place. It is a never-ending battle. Intriguing blog posts, inspiring speeches, and contentious twitter spats reshape our understanding of UX on a near-daily basis. However, some principles do endure.

This part of the book takes on the Herculean—and perhaps foolhardy—task of defining a core set of UX principles. The list is by no means exhaustive. A quick Google search of “UX principles” will return a long list of complementary approaches. As such, the following principles were selected to represent the enduring concepts shared among many approaches to user experience design and research.

User experience can first appear to be a big, scary monster of rules, contradictions, and dilemmas. While partially true, it is a monster easily tamed. We tackle one principle at a time, sear it into our memories, and become heroes to the users of what we create.