Hi, I was wondering if we can add other categories to the library catalog (http://www.boost.org/users/history/version_1_47_0.html). Here is a proposal Best, Vicente Domain Specific crc - Cyclic Redundancy Code, from Daryle Walker. units - Zero-overhead dimensional analysis and unit/quantity manipulation and conversion, from Matthias Schabel and Steven Watanabe. uuid - A universally unique identifier, from Andy Tompkins. Idioms base-from-member - Idiom to initialize a base class with a member, from Daryle Walker. compressed_pair - Empty member optimization, from John Maddock, Howard Hinnant, et al. Language Emulation: these are libraries are emulating a missing language feature exception - A library for transporting of arbitrary data in exception objects, and transporting of exceptions between threads (N2179), from Emil Dotchevski. move - Portable move semantics for C++03 and C++1 compilers, from Ion Gaztañaga scope_exit - Execute arbitrary code at scope exit, from Alexander Nasonov. typeof - Typeof operator emulation, from Arkadiy Vertleyb and Peder Holt. Patterns: libraries that implement a known pattern flyweight - Design pattern to manage large quantities of highly redundant objects, from Joaquín M López Muñoz. signals - managed signals & slots callback implementation, from Doug Gregor. signals2 - managed signals & slots callback implementation (thread-safe version 2), from Frank Mori Hess. State Machines meta state machine - High-performance expressive UML 2.0 finite state machines, from Christophe Henry. statechart - Arbitrarily complex finite state machines can be implemented in easily readable and maintainable C++ code, from Andreas Huber. System: libraries that are close to the underlying system chrono - Useful time utilities, from Howard Hinnant, Beman Dawes, Vicente J. Botet Escribá. date_time - Date-Time library from Jeff Garland. filesystem - Portable paths, iteration over directories, and other useful filesystem operations, from Beman Dawes. system - Operating system support, including the diagnostics support that will be part of the C++0x standard library, from Beman Dawes. I would add also the following to exixting categories Data structures optional - Discriminated-union wrapper for optional values, from Fernando Cacciola. tribool - 3-state boolean type library, from Doug Gregor. I have no suggestion for the following, so we can maintain them in Miscellaneous conversion - Polymorphic and lexical casts, from Dave Abrahams and Kevlin Henney. swap - Enhanced generic swap function, from Joseph Gauterin. timer - Event timer, progress timer, and progress display classes, from Beman Dawes. TR1 - An implementation of the Technical Report on C++ Library Extensions, using other Boost libraries as a basis, from John Maddock. utility - Class noncopyable plus checked_delete(), checked_array_delete(), next(), prior() function templates, plus base-from-member idiom, from Dave Abrahams and others. value_initialized - Wrapper for uniform-syntax value initialization, from Fernando Cacciola, based on the original idea of David Abrahams. The following libraries are already in another category lexical_cast - General literal text conversions, such as an int represented as a string, or vice-versa, from Kevlin Henney. numeric/conversion - Optimized Policy-based Numeric Conversions, from Fernando Cacciola. program_options - Access to configuration data given on command line, in config files and other sources, from Vladimir Prus.