Technical memento mori
The Latin phrase memento mori means "remember that you must die." It has been adopted into English to refer to an object that serves as a reminder of death, especially a skull. This is a common theme in art, such as Albrecht Di1/4rer's engraving St. Jerome in His Study.
I keep a copy of the book Inside OLE as a sort of technological memento mori.
At some point in the 1990's I thought OLE was the way of the future. My professional development as a programmer would be complete once I mastered OLE, and this book was the way to get there.
Most of you probably have no idea what OLE is, which is kinda my point. It stands for Object Linking and Embedding, a framework that began at Microsoft in 1990. It was a brilliant solution to the problems it was designed to address, given the limitations of its time. Today it seems quaint. Now I'm doubly removed from OLE: hardly any Windows software developers think about OLE, and I hardly think about Windows development. The thing I was anxious to understand deeply was irrelevant to me a few years later.
Despite my one-time infatuation with OLE, throughout my career I have mostly focused on things that will last. In particular, I've focused more on mathematics than technology because the former has a longer shelf life. As I quipped on Twitter one time, technology has the shelf life of bread, but mathematics has the shelf life of honey. Still, man does not live by honey alone. We need bread too, even if it only lasts a day.
Related post: Remembering COM