I run a company that sells online language-learning applications. I thought that I could also sell e-books. My question is - do I in the UK have to register for ISBN or ISSN? Is this obligatory, or I might as well publish my e-books without those numbers?
As far as I know, one can get ISSN number for free. Do you think it would be a good idea to apply for ISSN, and then publish my e-books under one name (it would be a series of e-books)?