This is taken from the Kennel Club's Illustrated Breed Standards Book.
An agile dog, powerful and speedy. His original purpose in Rhodesia was assisting big game hunters in the pursuit of their quarry, which often included lions. A feature of the breed is the ridge which runs in a tapering line down the back with two crowns, either side of the ridge, just behind the shoulders.
These days the Ridgeback is used in his native Africa as a guard dog. He is an excellent family dog, good with children, affectionate, and very loyal and protective to his family.
GENERAL APPEARANCE: Handsome, strong, muscular and active dog, symmetrical in outline, capable of great endurance with fair amount of speed. Mature dog is handsome and upstanding.
CHARACTERISTICS: Peculiarity is ridge on back formed by hair growing in opposite direction to the remainder of coat; ridge must be regarded as the escutcheon of breed. Ridge clearly defined, tapering and symmetrical, starting immediately behind shoulders and continuing to haunch, and containing two identical crowns only, opposite each other, lower edges of crowns not extending further down ridge than one-third of its length.  Up to 5 cms (2 ins) is a good average for width of ridge.
TEMPERAMENT: Dignified, intelligent, aloof with strangers but showing no aggression or shyness.
HEAD AND SKULL: Of fair length, skull flat, rather broad between ears, free from wrinkles when in repose. Stop reasonably well defined. Nose black or brown in keeping with colour of dog. Black nose accompanied by dark eyes, brown nose by amber eyes. Muzzle long, deep and powerful. Lips clean and close fitting.
EYES: Set moderately well apart, round, bright and sparkling with intelligent expression, colour harmonising with coat colour.
EARS: Set rather high, medium size, rather wide at base, gradually tapering to a rounded point. Carried close to head.
MOUTH: Jaws strong, with a perfect, regular and complete scissor bite, i.e. upper teeth closely overlapping lower teeth and set square to the jaws. Well developed teeth, especially canines.
NECK: Fairly long, strong and free from throatiness.
FOREQUARTERS: Shoulders sloping, clean and muscular. Forelegs perfectly straight, strong, heavy in bone elbows close to body.
BODY: Chest not too wide, very deep and capacious; ribs moderately well sprung, never barrel-ribbed. Back powerful; loins strong, muscular and slightly arched.
HINDQUARTERS: Muscles clean, well defined; good turn of stifle; hocks well let down.
FEET: Compact, well arched toes; round, tough, elastic pads, protected by hair between toes and pads.
TAIL: Strong at root, not inserted high or low, tapering towards end, free from coarseness. Carried with a slight curve upwards, never curled.
GAIT/MOVEMENT: Straight forward, free and active.
COAT: Short and dense, sleek and glossy in appearance but neither woolly nor silky.
COLOUR: Light wheaten to red wheaten. Head, body, legs and tail of uniform colour. Little white on chest and toes permissible, but excessive white hairs here, on belly or above paws undesirable. White toes undesirable. Dark muzzle and ears permissible.
SIZE: Dogs: 63 cms (25 ins) desirable minimum height at withers; 67cms (27 ins) desirable maximum height at withers; bitches: 61 cms (24 ins) desirable minimum height at withers; 66 cms (26 ins) desirable maximum height at withers.
FAULTS: Any departure from the foregoing points should be considered a fault and the seriousness with which the fault should be regarded should be in exact proportion to its degree.
NOTE: Male animals should have two apparently normal testicles fully descended into the scrotum.