A selection of great books at least tangentially related to transit maps and transit design. A note: some of the links below are Amazon Affiliate links – if you make a purchase after following one of these links, I make a small commission on the sale. An easy way to help support the site!

Johnson and Gill: Very British Types by Mark Ovenden. A intertwined history of two of the most recognisable British wayfinding typefaces: Johnston Sans (as used by the London Underground) and Gill Sans (as used by the LNER and now just about everyone).
$79.99 as a pre-order on Amazon.

While we’re talking about Mark Ovenden, I still highly recommend the new edition of Transit Maps of the World. A reprint has corrected a few of my complaints from my initial review, so it’s even better now! 
$23.33 on Amazon.

Frank Pick’s London by Oliver Green is an in-depth look at the visionary man who brought about the London Underground as we know it today.
$33.17 on Amazon.

Maps of London’s Transport by John Dodd. A superb collection of first-half 20th Century maps of train, bus, coach, tram and Underground maps. Some have never before been published!
$42.06 on Amazon

British Rail Designed, 1948-1997 by David Lawrence. A beautiful look at the history of graphic and industrial design of British Rail post-World War 2. I’m really looking forward to getting this for myself.
From $28.60 on Amazon.

Or you can get the reissued facsimile of the iconic 1965 British Rail Corporate Identity Manual instead. This one looks superb!
£75 from britishrailmanual.com

Speaking of identity manuals, the compact edition of the facsimile 1970 Unimark/New York MTA Standards Manual is simply superb.
standardsmanual.com

Peter Lloyd’s Vignelli Subway Maps is still the definitive work on that most divisive of transit maps.
$34.99 on Amazon.