  In contrast to the field, the binaries in dense stellar systems are
frequently not primordial, and could be either dynamically formed or
significantly altered from their primordial states. Destruction and formation
of binaries occur in parallel all the time. The destruction, which constantly
removes soft binaries from a binary pool, works as an energy sink and could be
a reason for cluster entering the binary-burning phase. The true binary
fraction is greater than observed, as a result, the observable binary fraction
evolves differently from the predictions. Combined measurements of binary
fractions in globular clusters suggest that most of the clusters are still
core-contracting. The formation, on other hand, affects most the more
evolutionary advanced stars, which significantly enhances the population of
X-ray sources in globular clusters. The formation of binaries with a compact
objects proceeds mainly through physical collisions, binary-binary and
single-binary encounters; however, it is the dynamical formation of triples and
multiple encounters that principally determine whether the formed binary will
become an X-ray source.
