Bio of Oswald Chambers:

Oswald Chambers was converted in his teen years by the ministry of Charles Spurgeon. Chambers studied art and archaeology before answering the call to Christian ministry. Author of the bestseller My Utmost for His Highest, Chambers has more than thirty other titles to his credit, all but one compiled by his wife, Gertrude.

See more at: http://arvellcraig.com/oswald-chambers-my-utmost-for-his-highest

Link to the devotional on YouVersion:

https://www.bible.com/reading-plans/792-my-utmost-for-his-highest