This is a fundamental reference book on models of organizations. While others try to sell their own pet theory, Morgan presents them all, exposing them to thorough scrutiny.
Any manager or student of management frequently gets confronted with situations that demand an ability to 'read' what is going on, and to generate responding answers and actions. Effective 'reading' needs models. Most of us rely on one or two favoured theories that habitually frame our thinking. However the choice of model is itself a limiting act - think in terms of mechanistic processes and you are limited to machine-based solutions.
Faced with a flavour-of-the-month theory - quality management, knowledge management, chaos theory, whatever - you can turn to this book and understand what type of theory it is - its assumptions, its benefits, its limitations.
Working in the other direction is slightly less comfortable. If you want the latest thinking on a particular perspective, you will find it summarised here, though not always accompanied by comprehensive signposts to follow-on reading.
Altogether quite awesome in its breadth.