In the structural genomics period traditional methods for protein crystallization have been eclipsed by automation using batch
or vapor diffusion equilibration to find conditions conducive for protein crystal growth. Although many globular and soluble
proteins predominantly from prokaryotes have been crystallized and their structures solved by high throughput approaches,
the remaining difficult proteins require more systematic and reflective methods combining miniaturization and integration
of modern and traditional crystallography techniques. One of these conventional methods is growing crystals in restricted
geometry, which is a historically well-known concept and a practical technique under-used by today's crystallographers. This
chapter presents practical guidelines to use capillaries for microbatch crystallization screening and counter-diffusion crystallization
as valuable techniques to obtain protein crystals in confined volumes. The emphasis in the authors' application is to perform
broad-based screening with a microgram amount of protein, optimize crystal growth in a supersaturation gradient, and undergo
in situ x-ray data analysis for x-ray crystallography without invasive manipulation. Applications and concepts presented here bring
to light future prerequisites for the next generation of automation for structural genomics.