Superseded by Steven C. Harper's Making Sense of the Doctrine & Covenants, which was written a quarter-century later. Two benefits of this volume that won't be found in Harper's work are:
- Extensive biographical information for each and every person whose name gets mentioned.
- Appendixes that include a section of the D&C removed prior to 1900, details about non-canonized revelations of Joseph Smith, and more.
Since the main purpose of this and Harper's work is to provide historical context for the D&C as we know it today, you're much better off going with the superior (and more up-to-date) treatment that you get from Harper.
This takes the notes of differing people and what they recorded when Joseph gave or had revelations. It is very interesting to see that people who hear the same message come up with varying accounts of what was said.