Burke’s Peerage, Baronetage and Knightage:

In NOBL, Holmes “picked a red-covered volume from a line of books of reference beside the mantelpiece” and read an entry for Lord Robert Walsingham de Vere St. Simon. I cannot say that whether the volume is Debrett’s Peerage and Baronetage or Burke’s Peerage, Baronetage and Knightage (first published in 1826), because both sport red covers. It is not inconceivable that Holmes owned both.