You may already know that the LDS Church has been updating the official church website with expanded information and clarification about topics that have caused some confusion for some members, such as multiple accounts of the First Vision, the process of translating the Book of Mormon, and the former ban on Priesthood ordination for members of African descent (rescinded in 1978).
On the issue of race and priesthood, the church clarified that the “justifications for this restriction echoed the widespread ideas about racial inferiority that had been used to argue for the legalization of black ‘servitude’” and that today “the Church disavows the theories advanced in the past that black skin is a sign of divine disfavor or curse, or that it reflects actions in a premortal life; that mixed-race marriages are a sin; or that blacks or people of any other race or ethnicity are inferior in any way to anyone else.“.
In addition to the church’s statement, I want to recommend an excellent post at the website of The John Adams Center where three members of the church offer faithful commentary on the issue of Speculation and Doctrine, specifically in relation to race and the priesthood and church’s statement:
Race And The Priesthood: A Forum Discussing The LDS Church’s Recent Statement
For an in-depth look at the 1978 revelation that lifted the ban, I recommend reading Edward Kimball’s comprehensive history:
Spencer W. Kimball and the Revelation on Priesthood
https://byustudies.byu.edu/PDFLibrary/47.2KimballSpencerb0a083df-b26b-430b-9ce2-3efec584dcd9.pdf (PDF Document)
I’ve linked to it before in a previous post but I also recommend an excellent essay by brother Marcus H. Martins, who was the first black LDS member to serve a full-time mission after the ban was lifted:
Thirty Years After the Long Promised Day: Reflections and Expectations
http://sixteensmallstones.org/wp-content/uploads/2012/04/Long-Promised-Day-Martins.pdf (PDF Document)