This sounds very suspicious. The email address of Academica Press is [email protected].

Dear Luigi Marongiu Not sure whether it is worthwhile. I see a number of red flags:

-The publisher “Academica Press” is not mentioned here http://wokinfo.com/mbl/publishers/?utm_source=false&utm_medium=false&utm_campaign=false listed here is some indication of legitimacy (when it comes to 'scientific')

-The contact info “1727 Massachusetts Avenue, NW, Suite 507 Washington, DC 20036” as mentioned here https://www.academicapress.com/contact does not look very thrustworthy

However:

-The distribution info https://www.academicapress.com/node/51 mentions “Mare Nostrum” which is also responsible for the distribution of the well-respected Thieme https://thieme.co.uk/contact-information/

So, in the end it depends on what you are looking for. A book published by for example Springer has a better reputation but when you are certain that the proposal here enables you to publish a book that is free of costs etc. it might be worthwhile.

Best regards.

PS. Though a Gmail address is indeed in most cases somewhat suspect there is a Gmail address mentioned here https://www.academicapress.com/node/369 The book mentioned in this link is advertised on various websites (just Google the title “Approaches to the Contemporary American Theatre”).