I should add I live in Winthrop MA (very close to Boston)

That sounds like a great idea for a gift. I can't speak from experience about these books, but a quick search brought them up.

http://www.amazon.com/Seaweeds-Available-Sustainable-Ole-Mouritsen/dp/022604436X?ie=UTF8&Version=1&entries=0

http://wildirishseaveg.com/two-cook-books-for-preparing-seaweed-at-home-are-launched-on-the-market/

https://seagrant.uaf.edu/bookstore/edibleseaweed/sg-ed-46a.pdf

It seems like there are 3 types of possible books - general beach guides (the first three), general seaweeds of our area but not limited to edible ones (the next 2) and seaweed cookbooks that might have guides (the last book.)

Salem Coastwatch lists these 3 general coastal guides for our area:

Eastern Tidepool & Reef: North-central Atlantic Marinelife Guide.

Harvey-Clark, Chris. 1997. Hancock House Publishers. Blaine, WA.

Marine life of the North Atlantic: Canada to New England.

Martinez, Andrew J. 2011. Aqua Quest.

Peterson Field Guide: A Field Guide to the Atlantic Seashore.

Gosner, Kenneth L. 1978. Houghton Mifflin Co. New York, New York.

I also found references to:

Seaweeds of Cape Cod and The Islands. John Kingsbury & Philip Sze. Bullbriar Press, RR1, Box 332, Jersey Shore, PA 17740

CJ Hillson. Seaweeds: A Color-Coded, Illustrated Guide to Common Marine Plants of the East Coast of the United States. 1977

Sea Vegetable Celebration. Shep Erhart and Leslie Cerier. ISBN 1-57067-123-0 Bookn Publishing Co. 2001 is a cookbook written by folks who work at a commercial seaweed producer in ME.

I also saw some online guides to edible seaweed such as this one. I wonder if it would be most useful if you chose one with good photos and had the pages printed on individual flip cards to be put into a notebook or a ring or printed on a large double-sided card and then either option could be laminated/plasticized at somewhere like Staples.