The Haynes Weber Carburetor Manual : Zenith Stromberg-Su Carburetor Manual (Haynes Techbook Series) by A. K. Legg, Don Peers, Robert Maddox, John H. Haynes
This book is amazing. I haven't read it cover to cover yet, but it looks like the highest quality Haynes manual I've seen. It covers a huge range of carbs, explains how they work, and has appendices for applications and jetting.
It covers Weber: DAF, DCD, DFA, DFV, DFD, DFE, DFM, DFT, DGV, DIF, IDA, IDF, IDS, IDT, DCNF, DCOE, DFAV, DFTA, DGAS, DGAV, IDAP, and IDTP. It has the illustrated step-by-step instructions with photo of installing dual 44 IDF's on a VW!! These are the instructions that "Hot VWs" published in 1995.
On top of that it also covers the Zenith Stromberg CD "constant depression" carbs: CD, CDS, CDS-2, CDSE, CD2E, CDST, and CDSET. Also covers SU H, HD, HS, and HIF as well as some odd auxiliary starting devices.
The illustrations are very good, black and white photos are good. Nice book.
Now I wish someone would do a book on adding those CD carbs to a Bug.