An account of the experiments used to explore the nature of universal gravitation that can be performed in a laboratory.

1. Introduction; 2. The linear oscillator driven by thermal noise and with electrical damping; 3. External sources of noise, and design of experiments; 4. The weak principle of equivalence; 5. Verification of the weak principle of equivalence for free particles; 6. Newtonian attractors of extended bodies; 7. Experimental tests of the inverse square law; 8. The constant of gravitation; 9. Conclusion; References; Index.