Hi McDermott - 1 lb of sugar is a lot for a five gallon batch. Beer recipes can be a little complicated -it's about balance, hitting the right targets for particular styles, etc. One of those variables is the ratio of fermentables in your wort, between base grains and adjuncts (sugar is an adjunct). Too much adjunct and your beer can become cidery, flavorless, or thin.
What recipe are you looking at doing?
When adding sugar to the boil, I do it at the end (final five minutes) to lessen the chance of carmelization or burning on the bottom of the boil pot.