The Elements of Typographic Style by Robert Bringhurst. The bible, that no designer should be without.
The Visual Display of Quantitative Information by Edward Tufte. The first of his ground-plowing series on efficient information design. Start with this one. (BTW, if you happen to have been at The Washington Post and find my original copy, I'd really appreciate its return. Signed, first edition. My fault for lending it out.)
The Shape of Design by Frank Cimero. Inspiring thoughts on creativity—reinforced by its beautiful design. Also set up as a website for those who don't feel tactility is an impactful aspect of reading. (Unfortunately the hardcover edition looks to no longer be in print, thus can't reliably vouch for the softcover.)
Road to Seeing by Dan Winters. Most auto-biographical books by photographers are too often a slog. This one is not. Inspiring and a beautiful object befitting the craftsman who is its author.
Self-Portrait, U.S.A. by David Douglas Duncan. Masterpiece coverage of the 1968 political conventions and my inspiration to pursue the black (and white) arts of photojournalism. Long out of print, but available online here and there.
Subtraction.com. Digital designer Khoi Vinh's interesting take on digital design and his personal love of film. Sign up for his daily newsletter.
Coverjunkie.com. If you need inspiration, this is the go-to site for the very best of contemporary magazine covers. Obsessively and lovingly (same thing, right?) curated by Jaap Biemans, art-director of Volkskrant Magazine.
Quartz for news (I'm a fan of their daily morning newsletter) and Medium for thoughtful bloggers. Both also happen to be stellar examples of digital design, where the annoying visual static—required for financial stability—is thoughtfully tamed.
Adobe CC suite. Indesign being the centerpiece for me. Illustrator, Lightroom, After Effects and, yes, good old Bridge.
Slack for projects with multiple participants and many parts to keep track of. (E-mail is not the place to manage projects.) Well-integrated apps for iOS.
Dropbox for routine file sharing; Wetransfer.com for one-off, big file delivery; Google-docs/sheets for open editing with teams.
Backblaze for off-site back up.
SquareSpace, for website design (of course), and Network Solutions for site backend and email.