Detailed enough for the enthusiast / fanatic, but light enough to read for the casual aviation buffs who want the real backstory - and not the 110 minute film version of everything. The weaving of four flawed individual lives and their workers who made the ideas happen, made this book hit the target. The power of co-operation and relentless hunt for the most workable solution in the given difficult circumstances, was the life lesson from this historical non fiction. Candles, electric lights paper and pencils - no computers. With this they helped win back freedom. A good read.