To delight in reading is to trade life’s dreary moments for moments of pure joy.

[Aimer à lire, c’est faire un échange des heures d’ennui que l’lon doit avoir en sa vie contre des heures délicieuses.]

Charles-Lewis de Secondat, Baron de Montesquieu (1689-1755) French political philosopher

Pensées Diverses [Assorted Thoughts], # 1632 / 1143 (1720-1755) [ed. Guterman (1963)]
    (Source)

(Source (French)). Other translations:

A fondness for reading changes the inevitable dull hours of our life into exquisite hours of delight.
[E.g. (1900)]

To love to read is to exchange hours of ennui for hours of delight.
[E.g. (1936)]

To love to read is to make an exchange of the inevitable hours of boredom in one's life, for some delightful hours.
[tr. Clark (2012)]