Terrorism is a beast with an extraordinary ability to mutate. As soon as its victims have learnt to cope with its methods, it develops new ones. Groups of anarchists throwing bombs follow the lone assassin who would target a king or a political leader. The hijacking of passenger jets is replaced by the transformation of aircraft into missiles against fixed targets.
All the time, the intention is to terrorise the largest number of people, eroding the ordinary man's confidence in the ability of the authorities to protect him, and, in the long run, persuading a majority of the people, who just want to live their lives, to trade their freedom for the security that the terrorist promises in his utopia.
Although new to India, the tactic of "symphonic" attacks has been tried in a number of other countries in the past decade, notably Algeria, Iraq and Saudi Arabia, at times with devastating effects.
Most recently, it was tried, on a smaller scale, by the Taliban in the Afghan city of Qala-Mussa. Theoretically, the tactic could be used in any city, from Bombay to New York, passing through London and Paris.
On Wednesday, it was obvious that India's various anti-terror units were surprised, unable to cope with methods of operations not mentioned in their manuals.
So far the only claim of responsibility has came from a hitherto unknown group using the name the "Deccan Mujahedin".
This may be a cover for other groups, perhaps the Lashkar Tayyiba (the Army of the Pure) and the Jaish Muhammad (the Army of Muhammad), two terrorist organisations created by the Pakistani military intelligence services.
Earlier this year, in one of his last acts as president, Pervez Musharraf announced the dissolution of both, but it is possible that the two groups and their backers in the Pakistani military and intelligence elite have returned to the market under a new brand, with new tactics.
The attacks came 48 hours after Pakistan's new president, Asif Ali Zardari, practically threw away 50 years of Pakistani policy by announcing his readiness to end the dispute with India over Kashmir.
Zardari is an ethnic Baluch who, unlike previous Pakistani leaders who had Indian backgrounds, has no direct family history in pre-partition India. As a result, he is not as sensitive on Kashmir as his predecessors.
The Bombay attacks could be a message to Zardari that, though he may be uninterested in Kashmir, the issue is still central to many in Pakistan.
The new label used may also be significant. Deccan, a region in south-central India, was the intellectual and cultural capital of Indian Islam for centuries.
By using the term "Deccan Mujahedin", the terrorists may be trying to pass two messages. First, that the Islamist movement is no longer interested only in Kashmir but intends to strive for the reconquest of the whole of India for Islam.
This runs in line with the new pan-Islamist thinking that propagates the will to recover all lands once ruled by Muslims – from India to Spain and southern France, passing by Siberia, parts of Russia and the Balkans. "Deccan" designates a movement that has universal aspirations precisely because it claims local roots.
The designation is also intended to show that India now has a home-grown Islamist terror movement.
This started to form more than a decade ago after Hindu nationalists won power in New Delhi through the BJP and its radical anti-Muslim allies. The Islamist terror movement has adopted what is known as the Matryoshka method, after the Russian dolls nested one into another. The outer and bigger doll in this case is the Students' Islamic Movement of India (Simi), which claims millions of members.
Indian authorities call Simi an antechamber of terrorism. Within it are nested other dolls in the form of cultural associations, charities and political lobby groups. The smallest and deadliest doll represents the kind of groups that may have been behind these attacks.
The need for a home-grown terror movement in India may have been further emphasised by the success of the US-led coalition in destroying virtually all Islamist training bases and safe havens in Afghanistan.
With Pakistan also becoming inhospitable, partly thanks to Zardari's apparent determination to move his country close to both India and the United States, Indian Islamists are forced to look for training centres and safe havens at home.
While many have mentioned al-Qaeda as the perpetrator of the latest attacks, the connection is not easy to establish.
Many experts believe al-Qaeda has ceased to exist as an organisation, although it survives as a model and inspiration. Al-Qaeda's number two, the Egyptian-born Ayman al-Zawahiri, has been calling on militants to refocus their efforts on winning power in Muslim countries such as India, which is home to 150 million Muslims, and thus the largest "Muslim" country in the world, ahead of Indonesia.
This is in contrast with Osama bin Laden's theory that the US and its Western allies must be prime targets because, if they fall, the world system they dominate will disintegrate, opening the way for Islam's final triumph.
It is possible that al-Zawahiri's writings influenced the Bombay attackers. But it is unlikely that he and al-Qaeda had any direct role in planning or executing them.
There are other reasons why India is targeted. Over the past five years, it has emerged as the largest aid donor to Afghanistan and the second most important backer of President Hamid Karzai's regime after the US.
The buzz in jihadist circles is that once the US and its allies have left, India will emerge as the principal foreign power behind the new democracy in Afghanistan. India is already playing a leading role in training and equipping the new Afghan army and police.
India has also moved from its traditional anti-Americanism to a new policy of close friendship with the US. Earlier this year, India signed a landmark nuclear co-operation agreement, paving the way for massive purchases of American military hardware in the future.
In jihadist circles, the new Indian economic boom is often described as the "House of the Spider", a reference to a sura of the same name in the Koran, Islam's holy book. On Wednesday, the attackers may have wished to show the flimsy nature of the "House of the Spider" by attacking Bombay, the engine of India's economic transformation.
However, if that was the intention, the terrorists are likely to be disappointed. Bombay and India in general have been victims of terror before, although not in so spectacular a fashion. And yet they have managed to absorb the shock and move ahead.
As always, the terrorists may end up like the man who, having won a great many tokens at the roulette table, is surprised when the casino tells him his winnings cannot be cashed.
Amir Taheri is author of 'Holy Terror: Inside the World of Islamic Terrorism'. His new book, 'The Persian Night', will be published next month. The Telegraph