Chess Tactics Art 3.0 - $45.95 (new stock May 09)
Program contains nearly 1,217 main examples with over 1,000 supplementary ones classified by tactical methods, combination motifs and difficulty (from amateurs to masters). Numerous text and visual hints to help the student find the solution.
The file size for download:
The program is the 3rd revised and expanded edition of the ever popular Chess Tactics Art by the Russian GM of Correspondence chess, Maxim Blokh. The focus of the examples' difficulty is on amateurs but even masters will find themselves challenged by the hardest ones.
No additional software required.