Why won't my bread raise the second time?

I'm using the Williams-Sonoma Kitchen Library "Breads" book. It's the third recipe I've tried, and everytime the bread turns out very dense. I'm following all directions--mix ingredients, let dough rise, knead briefly a second time and let rise again. It's the second round of rising time that is a dud. My yeast isn't expired, but it is older...could that be the problem?