William Henry Jackson quotes:

[The building of the transcontinental railway] was something truly earth-shaking and, whether or not there had been a dime in it for me, sooner or later I would have been out on the grade with my cameras.

Portrait photography never had any charms for me, so I sought my subjects from the house-tops, and finally from the hill-tops and about the surrounding country; the taste strengthening as my successes became greater in proportion to the failures.

And if any work that I have done should have value beyond my own lifetime, I believe it will be the happy labors of the decade 1869-1878.

Since 1873, I have been back four or five times. I have used the best cameras and the most sensitive emulsions on the market. I have snapped my shutter, morning, noon and afternoon. I have never come close to matching those first plates. (On photographing The Mountain of the Holy Cross)

In living, as in art, rules are drawn from practice; not the other way around.