Here are some books I've read that I highly recommend, with a link to them on Amazon. Learn about goal setting and motivation! There are plenty more out there!
Kindle vs Physical book? I recommend buying physical books for this type of information. You'll be able to refer back to sections quickly, and write notes right in the book. Some contain exercises or worksheets to complete. If you are really pressed for time and would prefer to have it on hand at all times, to access whenever you have a few minutes to spare, the Kindle or E-book might be best.