Ryôzanpaku Tiger's recommended reading list

In English:

History of karate. Autobiographies
Harry Cook "Shotokan Karate. A Precise History"

Hirokazu Kanazawa "Karate My Life"

Dictionaries

Schlatt "The Shotokan Karate Dictionary" (in German: Schlatt "Enzyklopädie des Shôtôkan")

Funakoshi Sensei's books.

Gichin Funakoshi "Tote Jitsu"

Gichin Funakoshi "Karate-Do Kyohan"

Gichin Funakoshi "Karate-Do Nyumon"

Gichin Funakoshi "Karate-Do. My Way of Life"

Philosophy

Teruyuki Okazaki "Perfection of Character: Guiding Principles for the Martial arts & Everyday Life"
Gichin Funakoshi "The Twenty Guiding Principles of Karate" (comments by Genwa Nakasone)

Technique of karate

Masatoshi Nakayama "Dynamic Karate"

Masatoshi Nakayama "Best Karate" series

Hidetaka Nishiuyama, Richard C. Brown "Karate. The Art of «Empty-Hand» Fighting"

Teruyuki Okazaki "Notes on Training"
Masahiko Tanaka "Perfecting Kumite" (in German: "Kumite in Perfektion")

Shotokan Karate Magazine

Internet resources

The Shotokan Way: Online Shotokan Karate Magazine and Research Centre 

In German:

Dictionaries
Schlatt "Enzyklopädie des Shôtôkan" (in English: Schlatt "The Shotokan Karate Dictionary")

Technique of karate

Masahiko Tanaka "Kumite in Perfektion" (in English: Masahiko Tanaka "Perfecting Kumite")

Fiore Tartaglia "Shôtôkan-Kata bis zum Schwarzgurt" 
Fiore Tartaglia "Shôtôkan-Kata ab dem Schwarzgurt"
Fiore Tartaglia "Bunkai der Shôtôkan-Kata bis zum Schwarzgurt" 
Fiore Tartaglia "Bunkai der Shôtôkan-Kata ab Schwarzgurt"
Roland Habersetzer "Koshiki Kata. Die klassischen Kata des Karatedô" (in French: Roland Habersetzer "Koshiki no kata - les formes anciennes")

P.S. The list will be updated and short reviews will be added. Osu!