My journeys to the various islands were regulated by the seasons
and the means of conveyance. I visited some islands two or three
times at distant intervals, and in some cases had to make the
same voyage four times over. A chronological arrangement would
have puzzled my readers. They would never have known where they
were, and my frequent references to the groups of islands,
classed in accordance with the peculiarities of their animal
productions and of their human inhabitants, would have been
hardly intelligible. I have adopted, therefore, a geographical,
zoological, and ethnological arrangement, passing from island to
island in what seems the most natural succession, while I
transgress the order in which I myself visited them, as little as
possible.

I divide the Archipelago into five groups of islands, as follows:

I. THE INDO-MALAY ISLANDS: comprising the Malay Peninsula and
Singapore, Borneo, Java, and Sumatra.

II. THE TIMOR GROUP: comprising the islands of Timor, Flores,
Sumbawa, and Lombock, with several smaller ones.

III. CELEBES: comprising also the Sula Islands and Bouton.

IV. THE MOLUCCAN GROUP: comprising Bouru, Ceram, Batchian,
Gilolo, and Morty; with the smaller islands of Ternate, Tidore,
Makian, Kaióa, Amboyna, Banda, Goram, and Matabello.

V. THE PAPUAN GROUP: comprising the great island of New Guinea,
with the Aru Islands, Mysol, Salwatty, Waigiou, and several