Tracking your research (the title of the book, page, publication date, publisher, etc.) has always been an integral part of research. However, sometimes there is more to it than that.
While reviewing digital files I saved to my flashdrive while in Salt Lake City at the Family History Library, I realized that I had the book title and page number, etc. What I don't have is the database that allowed me to search that book in the first place. Many scans of older books are parts of larger digital collections. What I did not track was the digital collection that contained scanned images (and searchable text) of the book. This would have been extremely helpful for when I want to search those books for names that were not searched for originally.
Lesson learned.