That being said:

It is possible to take too many notes; the task of sorting, filing and assimilating them can take for ever, so that nothing gets written.

The awful warning is Lord Acton, whose enormous learning never resulted in the great work the world expected of him. An unforgettable description of Acton’s Shropshire study after his death in 1902 was given by Sir Charles Oman. There were shelves and shelves of books, many of them with pencilled notes in the margin.

‘There were pigeonholed desks and cabinets with literally thousands of compartments into each of which were sorted little white slips with references to some particular topic, so drawn up (so far as I could see) that no one but the compiler could easily make out the drift.’

And there were piles of unopened parcels of books, which kept arriving, even after his death.

‘For years apparently he had been endeavouring to keep up with everything that had been written, and to work their results into his vast thesis.’

‘I never saw a sight,’ Oman writes, ‘that more impressed on me the vanity of human life and learning.’

Keith Thomas, writing in the LRB