To conceal his identity, the man's voice has been dubbed over .
He had a microphone concealed in his pocket.
The judicial and psychiatric heterogeneity might also have concealed possible deviations in working memory and\or planning present in certain subgroups.
However, skilful editing cannot quite conceal the notable lacunae within the book.
The language has an extraordinary transparency, unity and simplicity of shading; it conceals an exceedingly skilful control of detail and pacing, and a factual economy.
