Fluent interfaces are cool, but they throw away the semantics of the programming language like meaningful return values. The DSL in the article is a good examp

Fluent interfaces are cool, but they throw away the semantics of the programming language like meaningful return values. The DSL in the article is a good example of this problem: OrderId.StartsWith("a2d")...... So the StartsWith() returns a TransactionSearch, instead of a bool as you would expect. Once you do this often enough, you really get objects full of state-information, rather than methods with return values. An alternative to doing this is using Expression Trees, but somewhat harder (and not without faults) It would look like this: search.Where(s => s.Order.Id.StartsWith('a2d') && s.Customer.Website.EndsWith('.com') && ...) Two benefits come to mind: 1. StartsWith() can return a bool as you would expect. 2. You can use StartsWith() on strings, like OrderId --- I am not sure how you pulled this off in the DSL example (is OrderId a custom type, since you can't use Extension methods there?) The biggest drawback of course is: 1. Harder - You will need to parse the Expression Tree.