LyX is a document processor that provides the power and professional-looking typesetting of LaTeX with the familiarity of an easy-to-use graphical interface à la MS Word. Effectively, it provides the best of both worlds. For someone without knowledge of LaTeX, LyX is less imposing and has a smaller learning curve. But even seasoned LaTeX users who have no desire to leave their favourite text editor can take advantage of some of LyX’s features.
MS Word documents are often described as what you see is what you get (WYSIWYG): the document you edit is identical to what a printed copy would look like. Conversely, LaTeX is what you get is what you mean: you describe the document structure in plain text and all typesetting matters (headings, figure placement, numbering etc) are handled during compilation. LyX is the middle ground: you edit a document within which you can see images, tables, equations, big headings etc, but the final document is still compiled by LaTeX. Take a look:
Creating tables in LaTeX is challenging. A single incorrect character often result in a scrambled output that looks nothing like intended. Fortunately, editing tables in LyX is easy. If you require, you can simply copy and paste the automatically generated LaTeX source code.
Equations written in LaTeX code are almost indecipherable and therefore frustrating to edit. With LyX, you can edit equations in a WYSIWYG manner. It also accepts the keystrokes that LaTeX users are accustomed to. For example, type ^ and LyX will convert to superscript mode, type \nabla and LyX will convert it to a ∇.
LyX can do everything LaTeX can (it can even accept raw LaTeX code if you really need). Tables and equations were simply two examples of what LyX makes easy but LaTeX makes challenging.
Should you switch?
This post isn’t about trying to sell the idea of LyX to everyone, but rather to simply introduce a lesser-known option for document creation. In fact, I primarily use LyX only for its table-making ability. (Using a text editor and raw LaTeX just happens to suit my workflow better.) However, I have seen it be used to produce a whole thesis. I guarantee that it gave that author far fewer frustrations and a superior final product than if the same thesis had been written in MS Word.