APAD：The best laid schemes of mice and men

The best laid schemes of mice and men

The most carefully prepared plans may go wrong.

What's the origin of the phrase 'The best laid schemes of mice and men'?

From Robert Burns' poem To a Mouse, 1786. It tells of how he, while ploughing a field, upturned a mouse's nest. The resulting poem is an apology to the mouse:

Wee, sleeket, cowran, tim’rous beastie,
O, what a panic’s in thy breastie!
Thou need na start awa sae hasty,
Wi’ bickerin brattle!
I wad be laith to rin an’ chase thee
Wi’ murd’ring pattle!

.... ....

But Mousie, thou art no thy-lane,
In proving foresight may be vain:
The best laid schemes o’ Mice an’ Men
Gang aft agley,
An’ lea’e us nought but grief an’ pain,
For promis’d joy!

Still, thou art blest, compar’d wi’ me!
The present only toucheth thee:
But Och! I backward cast my e’e,
On prospects drear!
An’ forward tho’ I canna see,
I guess an’ fear!

John Steinbeck's 1937 novel Of Mice and Men revolves around the notion that, whatever careful plans are made, things don't always go as expected. It took both its title and its theme from Burns' poem.