GardenersCardiff answers:

I remember answering the same question in 9th grade and if my memory doesn’t fail me…I remember the poem “To a mouse” to revolve around the relationship between man, the most powerful creature on the earth and a mouse, who is weak and innocent. SO i guess that ties back to Steinbeck’s novel which involves Lenny, a man who’s mental instability is marked by his innocent and childish characteristics. ……so yeah….it basically shows the relationship between the powerful and the weak

GardenersCardiff answers:

The poem to which you refer, from whence came the title “Of Mice and Men” is called “To a Mouse” and is by Robert Burns. Here it is in standard english:
Small, sleek, cowering, timorous beast,
O, what a panic is in your breast!
You need not start away so hasty
With hurrying scamper!
I would be loath to run and chase you,
With murdering plough-staff.

I’m truly sorry man’s dominion
Has broken Nature’s social union,
And justifies that ill opinion
Which makes thee startle
At me, thy poor, earth born companion
And fellow mortal!

I doubt not, sometimes, but you may steal;
What then? Poor beast, you must live!
An odd ear in twenty-four sheaves
Is a small request;
I will get a blessing with what is left,
And never miss it.

Your small house, too, in ruin!
It’s feeble walls the winds are scattering!
And nothing now, to build a new one,
Of coarse grass green!
And bleak December’s winds coming,
Both bitter and keen!

You saw the fields laid bare and wasted,
And weary winter coming fast,
And cozy here, beneath the blast,
You thought to dwell,
Till crash! The cruel plough past
Out through your cell.

That small bit heap of leaves and stubble,
Has cost you many a weary nibble!
Now you are turned out, for all your trouble,
Without house or holding,
To endure the winter’s sleety dribble,
And hoar-frost cold.

But Mouse, you are not alone,
In proving foresight may be vain:
The best laid schemes of mice and men
Go often askew,
And leaves us nothing but grief and pain,
For promised joy!

Still you are blest, compared with me!
The present only touches you:
But oh! I backward cast my eye,
On prospects dreary!
And forward, though I cannot see,
I guess and fear!

…………………………………………………………………

As for why Steinback chose that line, to me the meaning is clear. The entirity of the poem is about a mouse whose home is lost. The home is crushed by a plough-staff. The line “The best laid schemes of mice and men
Go often askew”

(or the orignial “The best laid schemes o’ mice an’ men Gang aft agley, An’ lea’e us nought but grief an’ pain, For promis’d joy!)

not only sums up the poem, but also the novel by steinback (hence the title.) In the book, Lennie and George’s well laid plans go askew, and they too lose the “home” that they had worked so hard for (like the mouse in the poem). The line from the poem is so appropriate, and that’s why it makes for a good title.