PREFACE.
This book, written by Mr.Allen, bears both our names because we studied the material together, and settled what should be included and what excluded.

We discussed and disputed, and finally found ourselves in complete agreement.

We therefore decided to issue the book in our joint names, on the understanding that I should be allowed to disclaim the credit for writing it.

But the book would never have been written at all save for the inspiration and help of Mr.S.J.W.

Clark, who, in his travels in nearly every mission field, has brought an unusually acute mind, trained by a long business experience, to bear upon mission problems, and has done more hard thinking on the question of survey than any man we know.
Let anyone who doubts the need for survey study the present distribution of missionary forces.