The concept of the Lambda Architecture is centered around modeling complex computing systems as an ordered, immutable log of events. This approach allows for processing data as a series of transformations that output to new tables or streams, with each piece being independent and having defined inputs and outputs. The key property of this system is its ability to replay parts of the dataflow, making it easier to test and parallelize. What sets Lambda apart from other systems is its technique of writing data to two places, optimizing for both space and time, which allows existing map/reduce systems to be upgraded with a new fast track. The architecture itself isn't unique, but rather a sensible set of data engineering practices wrapped up under a catchy rubric, which can help people add low-latency fast tracks to existing big data systems.