Tex is a document preparation tool with possibly the best logo of all: a librarian lion. The whole of the academic science community use it to publish papers, theses, Research Wing Summer Ball invites and even full-length books. If you write essays of any significant length, be they undergraduate literature tracts or MBA reports, you should be using Tex. Why? Well at base level, for this simple reason:

Tex will save you hours and hours of reference ordering (citations/figures), section numbering, TOC rendering, layout formatting (fonts/margins/tables/lists/headers/colours/images) and Word processor crash-gazing.

Ok, so you're on board, otherwise you'd have surfed away by now. So let's address what Tex is, by way of oblique, poorly crafted metaphors.

The difference between Tex and a standard word processor like Microsoft Word is:

• The difference between an Audi engine and a Chevrolet chassis.
• The difference between the last kid606 record and all the software patches he used to make it.

First paradigm twist : Tex lays the document out for you. No messing around with pretty documents. It lets you focus on the technical content by dealing with all that for you.

Second paradigm twist : Tex doesn't have an interface, it's just the engine. For a nice interface on Mac use Texshop.

Third paradigm twist : In editing mode a Tex interface is just a plain text file with markup. No pages. No headers. No document. Just the document source. It looks kind of like if you do a right-click on this webpage and select 'View Source...'. Only much cleaner. Here's an example chunk from a latex document:

\subsubsection{Statistical Methods}
Naive Bayes is a supervised statistical method which can be used for clustering. Naive Bayes assumes data items are independent within each cluster, and simply estimates the probability of an item $x_i$ belonging to a cluster as the ratio of the frequency of $x_i$ in $c$ over the frequency of items in $c$~ \cite{Bayes}. So for a vector of data items \textbf{\emph{X}} and any cluster \emph{c}:

\begin{equation}
P(X|c) = \prod\limits_{j = 1}^k {P(X_j |c)}
\end{equation}

In this paragraph i'm naming a subsection, using mathematical symbols (the $ signs), emphasizing characters, citing a reference from my bibliography and dumping a formula in for good measure. I don't even want to think about doing that in Word. It takes ages. The markup will look pretty familiar to anyone who's used html tags to put links in their forum posts. This is exactly the same concept: tags. Once published this looks like:

As you might gather - this simple markup makes things extremely customisable. Tex will dynamically number and sort just about anything in your document, be it references, images, sections, subsections. In your document you can refer to each one through markup. This makes the entire structure of your document easy to play with.

Ok so this all sounds a bit technical, and to be frank, Tex is pretty complex and infinitely customisable, but, more importantly, it's just easy enough for a standard user to install and use.

On a mac your starting point is the i-installer which will handle the installation of all the modules required.

Additional reading in this tutorial from O'Reilly. A publisher that uses Tex exclusively to publish their books.