1 INTRODUCTION

2 H-ALPHA PHYSICS: FROM SFR TO LINE LUMINOSITY

3 MODELLING H-ALPHA EMISSION
3.1 H-alpha constraints from observational LFs
3.2 H-alpha bias constraints from simulations

4 SIMULATED H-ALPHA EMISSION FROM GALAXIES AND FROM THE IGM
4.1 The simulation
4.2 H-alpha IGM emission
4.3 H-alpha emission power spectra

5 SURVEYS OF H-ALPHA EMISSION

6 CONTAMINATION IN H-ALPHA OBSERVATIONS
6.1 Observed intensity of line contaminants
6.2 Power spectra of line contamination
6.3 Contaminants masking fractions derived from simulations

7 ALTERNATIVE FOREGROUND REMOVAL/AVOIDING METHODS

8 ASTROPHYSICAL CONSTRAINTS FROM GALAXY SURVEYS VERSUS IM SURVEYS

9 SUMMARY AND DISCUSSION