Amsterdam: Theatrum Orbis Terrarum for the World Publishing Co., 1965. First edition thus. Hardcover. Oblong quarto (26x 31 cm), xv (intro.), lxi, , 204,  pp. , 184 pp., 22 double-page charts; original mustard brown cloth, dustjacket. Very good in like jacket. Item #21923
"A basic hydrographical work for the seaman, completely different from Waghenaer's 'Spieghel der Zeevaerdt.' It is from the 'Thresoor' that Blaeu's and Janssonius' 'Light of Navigation' were mainly derived." (from jacket front flap.).