
Abstract 
1 
Introduction 
2 
Constants and Fundamental Physics 

2.1 
About
constants 

2.2 
The constancy of constants as a test of general relativity 
3 
Experimental
and Observational Constraints 

3.1 
Atomic clocks 

3.2 
The Oklo phenomenon 

3.3 
Meteorite
dating 

3.4 
Quasar absorption spectra 

3.5 
Stellar constraints 

3.6 
Cosmic
Microwave Background 

3.7 
21 cm 

3.8 
Big bang nucleosynthesis 
4 
The
Gravitational Constant 

4.1 
Solar systems constraints 

4.2 
Pulsar timing 

4.3 
Stellar
constraints 

4.4 
Cosmological constraints 
5 
Theories With Varying
Constants 

5.1 
Introducing new fields: generalities 

5.2 
Highenergy theories
and varying constants 

5.3 
Relations between constants 

5.4 
Models with
varying constants 
6 
Spatial Variations 

6.1 
Local scales 

6.2 
Cosmological
scales 

6.3 
Implication for the universality of free fall 
7 
Why Are The Constants
Just So? 

7.1 
Universe and multiverse approaches 

7.2 
Finetunings and
determination of the anthropic range 

7.3 
Anthropic predictions 
8 
Conclusions 
9 
Acknowledgments 
A 
Notations 

A.1 
Constants 

A.2 
Sensitivity
coefficients 

A.3 
Background cosmological spacetime 

References 

Footnotes 

Figures 

Tables 