J G Ballard is another of these writers I've been meaning to get around to for a long time. I chose Crystal World because I'd seen it hailed as a science fiction Heart of Darkness. Upon reading Crystal World I discover that one of the few things it has in common with Conrad's superb novel is that they both involve a trip into the jungle.

But comparisons with Heart of Darkness aside, Ballard's 1966 novel makes an engaging read. Crystal World is the story of Edward Sanders, a doctor in a leper colony, who receives a letter from two doctor friends, a married couple (Sanders had an affair with the wife) who run a small clinic on the outskirts of a Cameroon forest. They ask him to come to Mont Royal, where something strange is happening in the jungle. At last we are here, the letter reads, The forest is the most beautiful in Africa, a house of jewels... the people.... walk through the dark forest with crowns of light on their heads... The light touches everything with diamonds and sapphires.

Dr Sanders arrives in Mont Royal to find that the poetic letter wasn't just metaphor. The forest really is turning to jewels, undergoing some strange and rapid crystalline petrification that encompasses everything in its path - trees, animals, people. And there is evidence that it isn't just happening in Africa, but also in the Florida everglades. And perhaps other areas yet unreported.

There are two distinct levels to this book, the apocalyptic and the personal. Crystal World is apocalyptic, certainly, but gently so. The alluring menace of the encroaching crystallisation forms an unnerving backdrop to the tale, and within this landscape of brightly shining paralysis sits the knowledge, faint but firm, that we are watching a sluggishly creeping end to our world.

Against this apocalyptic backdrop is the deeply personal story of Dr Sanders, his existentialist journey into the forest, his encounters with its denizens (people who have been twisted and altered by the jungle's influence), and his ultimate confrontation with the deep and secret motives behind his humanitarian work.

The character of Sanders was well-crafted, complex and thorough. Despite this I didn't find him entirely sympathetic, and he was difficult to identify with. I also became increasingly irritated with Dr Sander's too slow acceptance of the obvious. I guess it made the story longer, but it did frustrate me on occasion. Other characters were less developed, more archetypal, but given the nature of the tale and the fact that the tale is written entirely from Sander's point of view, this is understandable.

Themes of dark and light are explored almost ad nauseam in the book (fanatical priest dressed in black, mad architect dressed in white; dark and mysterious former mistress, bright and sunny new love interest, glistening black Africans skin, diseased white leprous skin, etc etc etc), and often become bludgeoningly obvious. This lack of subtlety within an otherwise subtle and beautifully crafted book was often grating.

Ballard's treatment of his prose is lush but clear, but I felt his endless descriptions of crystals and jewels were a little forced at times. After all, how many ways can you describe a gem? I also found much of the language dated, which is excusable since this book was written in the mid-60s, but nonetheless it occasionally became an irritation.

But the aforementioned complaints are just minor distractions, and overall I found Crystal World to be a gem of a book, if you'll excuse the pun. Crystal World evolves at an easy and even pace, doles out it secrets in measured doses, meanders like a ponderous river through a petrified forest, slow but never dull, its landscape glittering mildly, holding us transfixed as we journey deeper and deeper into the light that lies somewhere in the heart of darkness.