Why does Jack London call this story "To Build a Fire" instead of "Building a Fire" or "The Importance of Fire"? Well for starters, it sounds a lot more poetic and nice. But the use of the infinitive "to build" (grammar nerd alert!) also makes the thought seem unfinished. Let's say someone walked up to you on the street and said, "To build a fire." You would stare at him or her and wonder, "Yes? What about it?"
The unfinished aspect of this title can actually convey a sense of yearning for fire that is unfulfilled, much like it is in the man's final attempt to save himself. After all, "To Build a Fire" in the frozen Yukon is one thing; to build a fire in the middle of a summer barbecue is another. By using such a simple title, London is able to make us reflect on how difficult a seemingly simple act can become when we change the setting behind it.