Should I include my second last name on the N-600 application, if my passport and social security card don't show it?

Properly identifying an applicant's name is just one of the details in immigration applications that can be significantly more complex than it may appear. Generally, in connection with a Form N-600 application for a Certificate of Citizenship, the applicant should identify her official legal name, regardless of whether she commonly uses only part of her name. To assure that the application process is properly completed and fully documented it would be wise for you to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options and strategies to attain your goals, and who then could offer legal representation in the often complex application process.