Mono.Collections is a library of highly optimized data structures and an API for
obtaining the most appropriate data structure based on capability needs and
usage.

The System.Collections namespaces consist largely of "Goldy Locks" data
structures which are designed for general use in the broadest possible set of
situations. While these structures have good performance, they lack the
aggressive optimizations possible with more specialized data structures.

The BCL collections API also suffers from a "type menagerie" design: users must
cultivate a familiarity with the available collection types and choose the
appropriate data structure for the situation. Any expansion of this menagerie to
include more, highly specialized structures would further degrade the usability
of such an API.

Mono.Collections provides an API through which users declare their capability
and usage needs and the library selects the appropriate specialized collection
type. This allows users with little or no familiarity with data structures and
complexity to capitalize on the knowledge and expertise of the Mono.Collections
authors. It also relieves users from the burden of knowing the available
structures and their particulars.