I have used the book myself and find it mostly helpful with family who were connected to wealth and land. One error I picked up was page 469 Lord Clinton and Saye. The second last paragraph refers to the marriage of John Trefusis, esq. who married Emma, daughter and Co-heiress of Tristram Colan. "Ann" and Elizabeth were the heiresses of Tristram Colan. Elizabeth married Francis Bluett esq. and resided at Little Colan. Her sister Ann married John Trefusis. I may include an (aka) on my tree (Ancestry), however I have not seen her referred to as Emma anywhere else. The further inference that Richard Trefusis was the son of Elizabeth Colan is therefore incorrect as well. I do not know who Richard Trefusis was, but this error throws the whole lineage from John Trefusis out of kilter. I believe this refers to the offspring of Ann (aka Emma) Colan and John Trefusis. If you have any connection to Trefusis in Cornwall, be carefull.
I know nothing about Tristram de Colan. If you come across anything about his wife or parents please let me know.
Colin Bluett