Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Long time since I read this...

...but, it remains a vivid memory; especially his research on 'pleochroic halos' (sic), concerning which I've never heard a persuasive argument against. Dr Gange presents difficult scientific concepts in layman's terms. I found his arguments well reasoned and persuasive; music to my ears, perhaps. A little read book that is rightly quoted by subsequent technical researchers.