For those who work often with typographic fonts, such as designers or typesetters, here is a good alternative to Font Book in Mac OS X to manage system fonts: Font Sleuth, whose second version brings some new features like the quick overview of all the letters with the ability to vary the color or size.
The search program has also been improved and include source groups configured by the same user in the sidebar. After testing I have to say that good advantage is that the application meets all of its functions in a discrete window in which all elements are concentrated in a style that is very similar to the Finder.
Font Sleuth need at least version 10.4 of Mac OS X to run and is priced at $ 12. But it is scheduled to rise to $ 15 (about 9.99 euros). Those who have the previous version 1.x can upgrade to implementing the second version is completely free.