Robert was a prolific chronicler of his artistic, emotional and intellectual life, keeping a journal entitled Diary Notes throughout the latter two-thirds or so of his life. In addition he produced a quantity of loose, single-sheet notes on various themes. ‘Aesthetic Note’ is his term for illustrations, generally watercolours, which usually include notes by himself and quotations by philosophers and writers exploring some topic of interest to the artist.

The Aesthetic Notes chronicle various of Lenkiewicz’s relationships, many of which were done solely by him while others were joint productions with his intimate partners. He encouraged many of his significant others to write journals during the course of their relationship with him, and some of these are richly illustrated, both by Lenkiewicz and his sitters. When Lenkiewicz’s partners agreed to create these journals, which often contain the most intimate private reflections of their authors, it was on the understanding that the notes would pass into Lenkiewicz’s possession, to be bound as books and kept in his library as an archive of material about obsessive behaviour.

Though some of the Aesthetic Notes were sold at auction after Lenkiewicz’s death, the bulk now reside in the archives of the Lenkiewicz Foundation.