1 INTRODUCTION  
2 OBSERVATIONS  
2.1 Hubble Space Telescope  
2.2 Chandra X-ray Observatory  
2.3 Ground-based Spectroscopy and Photometry  
3 STRONG GRAVITATIONAL LENSING ANALYSIS  
3.1 Multiple image systems  
3.2 Cluster Members  
3.3 Parametric mass modelling  
4 WEAK GRAVITATIONAL LENSING ANALYSIS  
4.1 Weak lensing catalogue  
4.2 Grid mass modelling  
5 COMBINING STRONG AND WEAK LENSING  
6 DISCUSSION AND CONCLUSION  
6.1 Comparison between different models  
6.2 Comparison with previous works  
6.3 The baryonic mass distribution  
6.4 A possible test bench for dark matter  
6.5 Summary & conclusion