Links:

Naturally, since there are no websites in English dealing with German travel law (see Preface), I cannot provide any respective links. As regards German language websites on this topic, entering "Reiserecht" into any search engine will turn up roughly a gazillion hits - go knock yourself out if you feel like it.
I will therefore limit myself to two select links to German sites:

Prof. Dr. Ernst Fuehrich's Reiserechts-homepage has a wealth of information on travel law- and tourism-related news. The author, Prof. Fuehrich, is undoubtedly one of the leading experts if not the leading expert on German travel law (see his books below). His website also includes a collection of reviewed travel law links (all in German) for further exploration should you so desire.

Prof.  Dr. Ronald Schmid's homepage is noteworthy, not only because it covers travel and air law, but furthermore because it is at least partly available in English, too: the section on air law is also available in English


Books:

Obviously, one wouldn't expect a lot of books on German travel law written in English. In fact there are none. Zero. Zilch. And while there are many books in German, including some really decent ones, your interest for an exhaustive listing and rating of all those German books is probably limited. I shall introduce you to the following three, though:



First and foremost Fuehrich's 
Reiserecht Handbuch,
currently 6th issue from 2010, 134 EUR. 1,300 pages. Comprehensive, it is not only an extensive annotation to the law text of  travel package law as well as the laws governing independent travel, travel agencies and travel insurance -  it is also the most thorough textbook and explanation on these subjects.
In fact, the next best thing for you to deal with German Travel Law in English would be to grab this book and a good dictionary. Unfortunately, I haven't yet come across a dictionary good enough to warrant recommendation. .. :-[




Then there is my dissertation thesis,
"Die mangelhafte Reise - Das Gewährleistungssystem des Reisevertragsrechts aus der Sicht des Reisenden und unter Zugrundelegung des Reisecharakters für eine einzelfallbezogene Ermittlung und Beurteilung der Mangelhaftigkeit" ("The Faulty Trip - the system of warranties within travel contract law from the perspective of the traveller and based on the trip character as a means of ascertainment and assessment of the degree of fault of the individual trip"), 1st ed. 2009.

As the title suggests it deals with travel package law exclusively, although the analogous application of same to individual booking of accomodation is also covered. It features not only an in-depth look at the matters of trip faults, liability and traveller rights, but also covers related areas such as a (short) history of both (German) package travel and (German) package travel legislation or e.g. the liability of the booking agency, and takes a detailed look at certain concrete issues of interest such as overbooking or force majeure/acts of god. At 49 EUR  for 540 pages it is a steal for an academic book!


Basiswissen Reiserecht, 1st ed. 2009, 20 EUR, is also from Prof. Fuehrich, and is intended as a textbook for students and hence much more compact (230 pages) than his impressive Handbuch above. Still it deals with all relevant aspects of travel law: package travel law is covered as well as individual travel law incl. air travel, and it serves its purpose well as an excellent concise introduction into German Travel Law.




Nb.: I do not get any money if you click these links, nor do I get any commission from amazon if you buy the books. The books are also available from any book dealer.