Alberto Savoia has shared his work-in-progress book on what he terms 'pretotyping', a way of testing and learning about nascent or conceptual product ideas, bringing them beyond the 'I wish I had something that could do this' and into the real where we can make reasonable valid decisions about what is right and what is wrong about that big idea.
Alberto summarises the process in two steps.
1. Make sure you are building the right product
2. Before you build it right
Two introductory cases 'cast' as pretotypes are engaging and readable (IBM speech to text, the Palm pilot). Alberto then describes a number of types and strategies for pretotyping.
Overall a useful and actionable body of work that can only get better.
Reference:
Pretotyping: A Different Type of Testing by Alberto Savoia