Sentence:  Good reviews look both backward and forward; an argument could even be made that one must look backward in order to discern the way forward, that backward and forward are two sides of the same research coin. Nowhere is such a <WSD>Janus</WSD>-like perspective more apparent than in the current set of reviews. 
Meaning of the word marked with <WSD> tags:  The god of doorways, gates and transitions, and of beginnings and endings, having two faces looking in opposite directions.