A 16 cm by 10 cm, hard-covered, field notebook. This “pocket-sized”, ~ 1 cm thick, notebook contains untitled, lined pages and was typically used by employees for taking notes around the Chalk River site. There is no indication of a date of manufacture but the words “Chalk River Project” on the reverse mailing address and the lack of a postal code would indicate it was probably 1960s vintage. (Postal codes came into usage in Canada in 1971.)