1. Introduction

2. Data Processing for Gaia DR2

3. Overview of the Contents of Gaia DR2

3.1. Astrometric Data Set

3.2. Photometric Data Set

3.4. Variability Data Set

3.5. Astrophysical Parameter Data Set

3.6. Solar System Objects Data Set

4. Scientific Performance and Potential of Gaia DR2

5. Treat Gaia DR2 as Independent from Gaia DR1

5.1. Gaia DR2 Represents a Stand-Alone Astrometric Catalogue

5.2. Photometric System Evolution

5.3. Source List Evolution

6. Using Gaia DR2 Data: Completeness and Limitations

6.1. Gaia DR2 Validation and Source Filtering

6.2. Survey Completeness

6.3. Limitations

7. Using Gaia DR2 Data: Additional Guidance

7.1. Time Stamping in Gaia Data Releases

7.2. Astrometric Source Model

7.3. Solar System Object Astrometry

7.4. Interpretation of Photometric Colours

7.5. Mean Magnitudes of Variable Stars

7.6. Use the Astrophysical Parameters with Care

7.7. Filtering to Create Clean Samples

7.8. Negative Parallaxes

7.9. Known Spurious Results

7.10. Take into Account Uncertainties and Correlations

7.11. Dealing with Underestimated Uncertainties and/or Systematic Errors

8. Gaia DR2 Access Facilities

9. Conclusions