In this book we present and confront the main comparative static results - effects of labor supply, demand and institutional wage movements - of the (a) basic two-sector model in six different scenarios: free market, partial (one-sector) coverage with perfect intersector mobility, partial (one-sector) coverage with imperfect mobility (Harris-Todaro), multiple (two-sector) coverage with imperfect mobility (Bhagwati-Hamada), partial (one-sector) coverage with affiliation restrictions in the covered sector, partial (one-sector) coverage with limited employment generation ability in the traditional uncovered sector.