55 kinds of concentration: 1. Unification of cognizance 2. Mundane 3. Supramundane 4. Concentration with applied-thought and sustained-thought 5. Concentration without applied-thought and with only sustained-thought 6. Concentration without applied-thought and sustained-thought 7. Concentration partaking of diminution 8. Concentration partaking of stagnation 9. Concentration partaking of distinction 10. Concentration partaking of penetration 11. Intentness with happiness 12. Intentness with pleasure 13. Intentness with equanimity 14. Intentness with light 15. Intentness with the sign of reviewing