The authors are Ed J. Pinegar, Richard J. Allen and Karl R. Anderson. I've started this with the D&C reading, so I'm only 2 chapters into it, but if you're looking for a companion study, I really like this one. I wanted to buy the Who's Who, but it didn't look like what I was looking for when I thumbed through it. I want one that tells me what was going on at the time and gives a good "rest of the story" about the people who are mentioned in the D&C if anyone knows of a good source.
This commmentary book I stole (Borrowed) from my in-laws. It wasn't my favorite. I like commentary that goes verse by verse. This one went by sections and sometimes when I had a question about a meaning of some verse, I couldn't find an answer. My dad was more helpful than this book. I will say that some of the quotes were good and the section on the priesthood was super helpful!
The chapters follow the lessons in the D&C gospel doctrine manual. It wasn't helpful for planning or giving lessons except that it got me thinking about the topic that I would be teaching in Sunday School class.