
Abstract 
1 
Introduction 

1.1 
Overview of the
subject 

1.2 
Plan of this review 
2 
Theory 

2.1 
Universality 

2.2 
Selfsimilarity 

2.3 
Mass
scaling 

2.4 
Type I 

2.5 
Coordinate choices for the dynamical systems
picture 

2.6 
Approximate selfsimilarity and universality classes 

2.7 
The
analogy with critical phase transitions 
3 
The Scalar Field 

3.1 
Field equations
in spherical symmetry 

3.2 
The black hole threshold 

3.3 
Global structure of the
critical solution 

3.4 
Nearcritical spacetimes and naked singularities 

3.5 
Electric
charge 

3.6 
Selfinteraction potential 

3.7 
Nonspherical perturbations: Stability
and angular momentum 
4 
More Spherical Symmetry 

4.1 
Matter obeying
wave equations 

4.2 
Perfect fluid matter 

4.3 
Collisionless matter 

4.4 
Criticality
in singularity formation without gravitational collapse 

4.5 
Analytic
studies and toy models 

4.6 
Quantum effects 
5 
Beyond Spherical
Symmetry 

5.1 
Perturbative approach to angular momentum 

5.2 
Axisymmetric
vacuum gravity 

5.3 
Scalar field 

5.4 
Neutron star collision in axisymmetry 

5.5 
Black
hole collisions 
6 
Acknowledgements 

References 

Updates 

Figures 

Tables 