An excellent English language bookshop if you're in Tallinn, if you're not please stop reading now...I think it's called 'Alecto' though a google search didn't yield anything (the second spelling showed a company of the same name but think it's unrelated).
But it's really there, I didn't imagine it. It can be found where Juhkentali peels off to the right from Liivalaia, on the right on the ground floor of an office building.
I was amazed to see multiple hardback copies of a history of the SBS, they must have picked them up cheaply somewhere, and generally a good military section if that's your bag, foreign language courses and dictionaries, fiction, biogs etc. Also a place that stocks a lot of ESL materials (booo!).
Generally nice for browsing and not a lot of folk about getting in the way.
Postscript: the shop is actually called 'Allecto', on Juhkentali 8.