The Importance of Being Earnest by Oscar Wilde

The Importance of Being Earnest (1895) is a farcical comedic play by the Irish author, poet and playwright Oscar Wilde.

From Standard Ebooks:
"The Importance of Being Earnest is Oscar Wilde's most popular play today, enduring thanks to its easy humour, witty dialog, and clever satire. It was also one of his more successful plays, despite its first run being prematurely ended after only 86 performances. The main characters pretend to be other people in order to escape social obligations, with the resulting confusion of identities driving the plot and the humour behind it."

This play is in the public domain and a free ebook is available here. There are also multiple copies at the Stockholm public library.