LaTex is a system which produces high--quality scientific documents. It is to be distinguished from a word processor in that it can do a professional--quality job in setting the equations, tables and figures along with the numbering of all the parts of the document (including the equations. It will do all of this if it is given the commands for how to organize the document, but in general you will not see the final form of the document as you are working on it. In this way TeX is similar to the HTML that I am typing at this very minute. It is a plan for the organization of the information that you have. In the end, the result will be better than that of any common word processor. But there is a price to pay. The "document" you prepare is much like a computer program and it is possible to make mistakes so that you have to correct them.
It is also a Good Thing if the document plan you make up can be used on many different computer systems... not everybody runs Unix! Not everyone runs Windows on a PC or uses a Mac. Everyone should be able to view your work. So it is also a Good Thing if the software used to process this document is universal and stable so that we don't have to worry about the different versions. And it would great if the software was FREE. LaTeX satisfies all of these needs. It has become universal language among mathematicians and scientists and you need to learn it.
Yes, producing a big document like an illustrated book will take lots of time. But to produce a simple document with a few equations is not hard and you can do it with the examples I give here. Then (if you want) you can work your way up to more complicated things.