I find it hard these days to find techincal books that contain much I wasn't already familar with. This books jammed packed with things i didn't know or was only vaguely aware of. Almost none of the material i've seen covered anywhere else. From page one till the end I though wow, i've learned something new with every page. Its definately one for the techi, but when you covered all the rest this book takes you inside active directory to places you never though you'd go.
It talks about the database that is active directory, objects (user, computer, OU ) about attributes of those objects (e.g. Directory Name / objectClass / sAMAccountName ). You learn to manage/add attributes ( Give users attribue of employeeID ). How to update attributes of an object (say changes user daves employeeID ). How to access AD as a database using script not forced to use windows MSC consol (dsa.msc) which is so limited. Changing permissions on attributes allowing users or groups to update attribues (allow users to update their own telephone numbers). Much work is done using adsi.msc
There is extensive information on searching AD using the saved searched folder in DSA.msc. Searching is mostly done with LDP.exe, once you've learned how to search you can incorporate that into vbscript, to write scritps that find searched for objects then apply whats leaned in managing objects to move / delete / update / display attributes of those objects. You will learn to search for anything you could imaging (people called dave, disabled accounts, deleted things (yes you can find things deleted from AD) people in Manchester office, workstations that have been logged into more that 100 times)
There are great vbscript examples that will get your ideas flowing and get you well on your way. There is so much i've not mentioned its really teaching you to view/access AD as a database who's objects and attributes and security are in your control. Even if your not interested in scripting it will teach you so much about AD objects and attributes its still worth it.