How do you think you lost your Contacts? In any Android system, they are quite informative. If you stored nothing more about a contact than the telephone number, that's all you get. There are places in Contacts for any amount of detail but you have to tap the Add another field to expand the information you give the system.
Beyond the options for three types of phone numbers and e-mail address are IM, Address, Notes, Nickname, Website, Internet Call (Skype as an example), Events and Relationship.