This thesis investigates several macroeconomic aspects of labor markets. First chapter finds that in the US more educated individuals experience lower and less volatile unemployment due to a lower hazard rate of losing a job. A theoretical model with initial on-the-job training illustrates that accumulation of match-specific human capital can explain this empirical pattern. Second chapter develops a theoretical model with state-dependent wage setting. The model predicts that higher wage bargaining costs lead to higher and more volatile unemployment, consistent with some cross-country empirical evidence. Third chapter proposes a method to indirectly measure job-embodied technical change by using data on job tenure. The results show th...