The classification of living things relies on the concept of a single organism, which can be treated separately from those organisms with which it interacts. In 'Liaisons of Life' Tom Wakeford argues that in fact most organisms are involved in symbiotic relationships, for example many plants are connected to an underground system of fungi, which provides them with vital nutrients. He argues that and this calls for a new way of looking at living things. He also shows how the idea of symbiosis has met a great deal of resistance. Beatrix Potter, for instance, might have devoted her life to the study of lichens if her early research showing their symbiotic nature hadn't been ridiculed.
One criticism I would make is that Wakeford tries to cram too much into some of the chapters, so that the ideas introduced become something of a blur. Into this he throws lots of examples of the 'loner against the establishment' type. This is all very well, but I feel that such examples need more careful consideration for them to be convincing. But the material is presented in a non-technical way and it's an entertaining book to read, so if you want to take a look at the effect the symbiotic viewpoint is having on the biological sciences then I would recommend you to read this book.