Joseph Fielding Smith, Jr. was the tenth president of The Church of Jesus Christ of Latter-day Saints (LDS Church) from 1970 until his death. He was the son of Joseph F. Smith, who was the sixth president of the LDS Church. His grandfather was Hyrum Smith, brother of LDS Church founder Joseph Smith, Jr., who was Joseph Fielding's great-uncle.
The first half has some great doctrinal commentary, but the second half is outdated instructions on the practicalities of family history work and is almost entirely irrelevant in today's era of Family Search.