A PDF — which stands for Portable Document Format — is an open standard document file extension created by Adobe. It has gained popularity in recent years because of the ease of use it affords the ...

Gimp is normally used to create or manipulate images files, but can also work with PDFs if you understand how it works and what it's limits are. If you’ve never used Gimp—a free image editor available ...

Mr. Stulberg writes about excellence and mental health, and is author of the new book “Master of Change: How to Excel When Everything Is Changing — Including You,” from which this essay is adapted.