I've written a few. One, for example is about MLM marketing (aka Network Marketing). It took me a few weeks, on and off, to write it. I wrote it myself, based on my experience, so it didn't take long and I didn't need any help. Basically it discusses what to look for in a MLM company, products, and compensation plan. If ALL criteria are not satisfied, fuggedaboudit. Lots of luck finding good ones. I'm not in any now, and am not promoting any.
If you are in one or looking, are you sure you will not be wasting your time?