ericmattingly wrote: My question involves the others. Are these other books each discrete sets of discourses-- that is, do they each have their own suttas with no or very little repetitions from the others? If I dig "In the Buddha's Words" and decide, say, to buy the Middle-length discourses is there any reason to later purchase the Long and Connected discourses (and, apparently, the forthcoming Numbered ones)? I guess what I'm asking is what the textual history of these collections is. Have they been compiled out of the Sutta Pitaka by the editors and translators, or do they have a deeper history? What is a "connected" discourse, and why are the others not connected? What about the smaller discourses? etc., and so on. I'm sure the books themselves explain it all very thoroughly, but I must spend my money wisely these days, and it mostly goes to food and gas.
The sutta pitaka is comprised of the Majjhima, Digha, Samyutta, Anguttara, and the rest. Without these there is nothing left.
Each book contains material arranged around a theme, or guiding principal. This means that some overlap of material has occurred, and so each book contains within it some suttas from the other books. An example would be Digha Nikaya sutta 22 and Majjhima Nikaya sutta 10, which are very much the same sutta, only with the end of DN22 having an expansion on a point of doctrine. Also in the DN we have the 16th sutta, which contains within it many scenes which are accorded sutta status of their own in other books (several being found in the Samyutta Nikaya).
In addition to the common inclusion of this or that sutta, there is the common use between suttas and books of various 'periscopes', or stock passages. These are numerous and scattered widely, especially among the four main books of the Digha, Majjhima, Samyutta and Anguttara.
I cannot say exactly why there are more than one book in the sutta pitaka, except that each book is thought to have been aimed at differing parts of the Buddhist community (as well as those outside it). For example, I have read that the Digha Nikaya is thought by some scholars to be a propagandic book, aimed at those members of the predominate Brahmanism society of India who were interested in the teachings of the Buddha. Compare this to the proposed intent of the Majjhima Nikaya: that it was aimed at new monks and nuns, in order to give them a firm grounding in doctrine, practice and culture. The Samyutta was suggested (perhaps by B. Bodhi?) to have been aimed at those within the monastic community with a penchant for more detailed discussion of the doctrine, while the Anguttara was aimed largely toward the laity, hence its many suttas about lay life.
The smaller books are of various ages, and it is not agreed among Theravada pracitioners, and less so those that study the canon from outside any one tradition, which among them are from the Buddha's mouth or from the first generation of monks and nuns, and which have come from more recent commentators. For example, the Dhammapada is thought to be old, as well as the SuttaNipata, whereas the books on Divine abodes and ghosts are thought to be more recent.
Lastly, the naming of the Samyutta comes from the way that Nikaya is organized internally, where each section contains many short suttas all discussing one very specific point of doctrine. These suttas are "yolked together", Sam-yutta, by their common theme and subsequently massed together in their own specific chapters. The Anguttara,in comparison, is called the "Numerical book" because each chapter is organized by how many doctrinal elements are contained in the suttas it contains. For example, the eleventh chapter has suttas that each elaborate eleven elements of doctrine.
Anyway, welcome to the forum. Hopefully I didn't miss the intent of your post, and have helped answer some of your questions.