In reply to my inquiry about this book, I received further details for its purchase:
"An updated edition of this work was published two years ago under the title "The Landed Families of Perthshire Vol. 1 The Earldom of Strathearn" the publisher being Perthshire Heritage. The ISBN is 0954562801 with which you can order it from virtually any bookshop. Being the author I have several copies left and could mail one to you if you wish. The price if £35 plus £10 postage and packing. Alternatively you could order it through www.gardners.com a very large bookseller based in England who may be able to offer you a better deal on the postage and with whom you could pay by card".