What book do you recommend for learning about Linux Servers? [closed]

I'm mainly a developer, who recently took a liking to Servers.

Most of my tinkering has been with Microsoft Windows Server 2003/2008, but I'd like to go down the rabbit hole and see what things Linux offers.

For example, MS has Active Directory - does Linux handle something like this? What do they have?

I'm an absolute beginner to Linux sysadmin (I've used Linux normally as an end user though), what book and distro would you recommend I start with?

This is just for hobby and to broaden my knowledge because I love learning. :)

Thank you for your time.

The Unix and Linux System administration Handbook is good.

I got my start with some of the open source manuals and books from The Linux Documentation Project.

Ubuntu and its variants are very solid and popular. It also has its own StackExchange. I prefer Debians based system such as Ubuntu to Redhat. Years ago, the packaging system was far superior although I believe Redhat has added similar features. Pretty well any distribution will do. I have no problems switching distribution as required.

EDIT: As noted the Unix System Administration Handbook (frequently updated and now renamed) is a good reference. Not something you want to read cover to cover. Work through the appropriate chapter as to need. It is very accessible and covers things well. It is one of my essentials on my bookshelf.

For Firewalls, I find the documentation for Shorewall to cover pretty well anything you can do. Documentation covers enough theory and practice that you can use it with other firewall builders.