Master-Child Child-to-Parent Query Example

SalesforceSession salesforceSession = new SalesforceSession(new LoginDetails("username@example.com", "salesforcePassword"));  
ContactDataSource contactDataSource = new ContactDataSource(salesforceSession);
List<Contact> contacts = contactDataSource.QueryEntities<Contact>(
      Contact.Fields.Id, 
      Contact.Fields.FirstName, 
      Contact.Fields.Account(Account.Fields.Id, Account.Fields.Name)
);

foreach (Contact contact in contacts)
{        
	Account account = contact.Account; //get the related Account
	string accountName = account.Name;
}