Here is a link to the article, which was originally printed in Harvard Business Review. The authors are William Oncken, Jr., and Donald L. Wass: Who’s Got the Monkey?
This article changed how I look at everything, even outside of my business life. Long live the monkey! Unless you can’t feed it. Then, bye-bye monkey! (1)
This version of the article includes a commentary by Stephen Covey, added when the article was republished a generation later. IMHO, you could skip that.
(1) No real monkeys are harmed in the preservation of your sanity.