This will suffice as one resource among many.

This is a (IMO on-demand) chapbook reprint of a 1998 book listing all of the descendants of John Simpson from an earlier 1956 book.

There is a brief biography of the Reverend, but a lot of the history from the 1956 book is missing from this edition.

Nobody that wasn't in the 1956 book is in this one.

There's a big section on how to use some software from a CD that accompanied the 1998 edition, but there is no CD. (The software probably couldn't run on a modern PC amyway).