Unfortunately, I don't know the literature on this field that well, just the general background. -) So I know how most of the techniques work, who some of the experts are on a couple of the topics, and I can point out if a particular source doesn't seem to understand the science. But I would say that it's too broad a topic (and not enough is known) for it to be covered in the scientific literature as a single unit. 

That said, these reviews might be useful - please let me know if I can explain anything for you. I've just added them to a couple of articles, so you may come across them in Wikipedia as well. -) I can also recommend more sources on any specific topics of interest. 

Gene therapy is the field that's furthest along. Related articles of interest include vectors in gene therapy (aka delivery methods) and genome editing. There are also techniques such as SCNT (where the entire nucleus is replaced - this is how Dolly was cloned), but I hesitate to consider those genetic engineering. 
Another field that comes to mind is regenerative medicine, although that article isn't nearly comprehensive. This (and the related field of tissue engineering) mainly focus on applications such as the growth of organs for transplant, starting from stem cells. However, it doesn't currently use much genetic engineering; the closest it gets is genetic reprogramming (I was extremely surprised to find that article didn't exist; I've just created it.)
As far as I'm aware, the use of genetic engineering to give humans new traits (as opposed to prevention or cures) is mostly speculative, although the techniques should apply in the same way. Synthetic biology is the closest (in that it attempts to devise new traits), but it's still just beginning and is extremely far from any application in humans. I imagine that most of the descriptions of technology will be like this (not yet applicable to humans but could be in the future), other than that which applies to human cells in culture.
The scope of the article is uncertain to me. Most of the sources that use "human genetic engineering" as a viable description discuss ethics rather than science. (Of course, the ethics is important as well, but my familiarity is with the science.) There is a lot of scientific detail that can be discussed, but as I mentioned above, the science itself doesn't usually use such a broad categorization. 
The science is moving quickly. An article written in 2012 may have a significantly different background context from one written in 2011. 
Modification is easiest at the zygote or blastocyst stage. There is a bit of information on how this is done at transgenic mouse. (It's not done in humans, of course.)
There are a lot of people who use language such as "the next stage in human evolution." (This is something I removed from the article.) I think I also saw it in a couple of respectable sources when I was editing this page, but it's at the least imprecise/poor wording and (at least in my opinion) should be attributed if included. It is valid under a broader definition where "evolution" simply means "change over time," but it implies some mechanism of progress or goal-directedness ("stages") - so it is somewhat misleading when applied to biological evolution, which doesn't have these properties. 

I won't be available much for at least the next few days, but please let me know if you have any questions. -) If it's more than a week, please feel free to remind me on my talk page (since the message will drop off my watchlist).