If you use Debian or CentOS, the automated installer is available from the distributor. Slackware does not provide one. The book you recommend gives a sample script to write your own installer. This might be more useful if the Slackware site had a link to the book, but I don't see one.

"One or another" sums up the problem. To take an example, most institutions I've every worked for use office suites. Slackware is the only Linux I can think of that doesn't include OpenOffice or LibreOffice in its repository. Well, Doudou and Qimo don't, but they're for children under 10. Most packages are indeed available for Slackware: once you discovered which repository you need.

I don't usually feed the trolls, but this post was typical of what makes Slackers figures of fun. As I said, it's a perfectly good distro for certain purposes, but you aren't going to find it in an enterprise environment. Search on-line for businesses running Ubuntu, and you get Google and Wikipedia. Search for businesses running Slackware, and you get a post from 2013 about one with 7 computers and another which went bust.

While this thread is old I simply have to correct the final statement. First Slackers have a reason to be defensive about how Slackware is represented, or should I say misrepresented, by non-Slackware users. The previous post, although they list Salix as a system they use, is not correct in both of their sited cases.

1) Slackware has a standard automated installer at boot time of the ISO and standard package manager(s). They are both CLI/ncurses presentation and have automated steps in the installation process and check for package installation and updating.
2) Slackware included documentation on the boot disk from the distributor tells you how to install over the network and what repositories are available to get your desired package. The standard repository has tens of thousands of packages available.
3) The standard Slackware install installs a full KDE package that includes the Caligra Office suite, which has the same applications as Apache OpenOffice and LibreOffice. The Caligra Office suite has the same touch and feel as OO and LO and maintains compliance to Open Document standards. The fact that Microsoft doesn't' support Open Document standards is a different issue so don't' flame here about docx and xlsx, the leashes of Microsoft which are proprietary and lock a user into license renewals and loss of backward compatibility for documents and archived materials.

The OP is looking for a Linux to learn from and to prepare for an administrator position in an enterprise. Slackware is the most *nix like Linux available and will prepare the OP to not only administer Linux but also Unix. But again the OP should look for LIVE CD's of multiple Linux distributions (or BSD also) and see which they feel might better teach them Linux and its administration.