1. An overview of biochar application in soil to immobilize heavy metals 2. Biochar's surface properties 3. Mechanisms underlying biochar induced heavy metal immobilization 4. Biochar application to immobilize heavy metals in different soil systems 5. Biochar's effect on soil properties 6. Assessment of heavy metal stability in biochar-treated soil 7. Long-term stability of heavy metals in biochar-treated soil 8. Biochar field cases at contaminated sites 9. Engineered biochar for heavy metal immobilization 10. Summary and perspectives