Using  more literary than philosophical sources, though there is a section on Heidegger’s idea that boredom was the ideal state for metaphysics to begin, Lars Svendsen provides a series of sketches on the theme of boredom.

Svendsen argues that boredom is significant because it involves a loss of personal meaning. Boredom is a modern condition, though there were similar historical states (the acedie of monks). With the advent of Romanticism, man began to see himself as an individual. At the end of the eighteenth century the word ‘boring,’ linked with the word ‘interesting,’ became widespread. Shortly afterwards, boredom is also linked with nihilism, which converge in the death of God. There is a kinship or overlap between boredom, melancholy (but without its charm) and insomnia.

[..] deep boredom is related, phenomenologically speaking, to insomnia, where the I loses its identity in the dark, caught in an apparently infinite void.

There are no reliable studies but evidence suggests that boredom is increasing. Its increase implies a serious fault in a society or culture. Neither leisure, nor work offer a respite from boredom because neither give any real meaning. We seek distraction and differences. The advertising industry flourishes to create these qualitative differences where there are none. In my favourite parts of the book, Svendsen uses Bret Easton Ellis’s American Psycho and Ballard’s Crash to build his argument of a profoundly bored late capitalist society.

Desperately seeking external distraction we turn to television:

But are not the extent of the entertainments industry and the consumption of intoxicants, for example, clear indications of the prevalence of boredom? People who watch TV four hours a day will not necessarily feel or admit that they are bored, but why else should they spend 25 percent of their waking hours in such a way.

Or build an ‘extended family’ of celebrities:

That boredom is probably more widespread than ever before can be established by noting that the number of ‘social placebos’ is greater than it has ever been. If there are more substitutes for meaning, there must be more meaning that needs to be substituted for. Where there is a lack of personal meaning, all sorts of diversions have to create a substitute – an ersatz meaning. Or the cult of celebrities, where one gets completely engrossed in the lives of others beaches one’s own life lacks meaning.

Or like Bateman in American Psycho obsess about fashion:

As Georg Simmel points out, dependence on fashion indicates the insignificance of the own personality, that a person is incapable of individuating himself.

Svendsen suggests only one possible cure for boredom: to relinquish personal meaning. He uses Beckett and Warhol as examples of people who have tried to embrace meaninglessness.

There is possibly one sure cure for boredom – to leave Romanticism behind and renounce all personal meaning in life. In a sense this was what Beckett did, but his work concerns itself mostly with the vacuum that is left.