This download contains a compiled help file (chm) of all the available Lync Server 2010 IT professional documentation on the Technical Library

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9720c3f1-ddd4-426b-b98a-f1205561ce00&displaylang=en

If you want the online version you can go here http://technet.microsoft.com/en-us/library/gg398616.aspx

Enjoy…