His memory of that period of history is fragmentary.
Tips
usage
Used for physical objects (books, artifacts, ruins) and abstract things (memories, records, evidence). The two halves 残缺 and 不全 reinforce each other — both mean 'lacking parts.'
memory
Each character pulls in the same direction: 残 (damaged), 缺 (missing), 不全 (not whole). The redundancy is the point — total emphasis on incompleteness.