1. Introduction

2. Observations and Data Analysis
2.1. The 400d weak lensing survey
2.2. Weak lensing analysis
2.3. Choice of the overdensity contrast
2.4. X-ray analysis
2.5. Mass Estimates
2.6. Fitting algorithm for scaling relations

3. Results

4. A mass-dependent bias?

5. Comparison with previous works

6. Summary and conclusions