The notebooks include descriptions of paintings, drawings and sculptures as well as biographical details about painters and collectors, comments on the architectural features of some of the houses he visited, and information about the provenance and future plans for the sale or relocation of some of the paintings he viewed. Some of the notebooks contain Kay's sketches of individual works.
A number of entries relate to Kay's work for the Estate Duty Office. These have been indicated by an asterisk (*) at the end of a description.
Some notebooks contain updated information added after Kay's death.
Most of the notebooks include indexes. In general, those found at the front of a notebook are indexes to the individuals Kay was visiting and relate to his work for the Estate Duty Office; those at the back of notebooks tend to be indexes to artist, subject, place or a mixture of all three and relate to his work for the National Gallery. If a notebook has been indexed, this has been noted in the relevant description.