The expression Baedeker raid (also Baedeker attack, etc.) designates one of a series of raids by the German Air Force in April and May of 1942 upon places of cultural and historical importance in Britain.

This expression refers to Baedeker, designating any of a series of guidebooks to foreign countries, issued by the German publisher Karl Baedeker (1801-1859) and his successors.

The Germans officially stated that those air raids were carried out in reprisal for the bombing of the Hanseatic cities of Lübeck and Rostock, and that the Luftwaffe’s targets were all the buildings in Britain that were marked with three stars in Baedeker’s guidebooks. This was reported, for example, by the following two British newspapers:

1-: By the Evening Despatch (Birmingham, Warwickshire, England) of Tuesday 28^th April 1942 [No. 15,850, page 1, columns 2 & 3]:

NAZI PLAN TO BLITZ HISTORIC BUILDINGS

ALL pretence that the German “reprisal” raids are directed against military objectives has now been dropped. The German Press openly admits that they are directed against residential districts and historical monuments.
The “Boersen Zeitung” gave lists and descriptions of the historic buildings and institutions which, it says, were hit at Bath and Exeter, and says: All these things are now only “historic memories.”
German officials are quoted by Berlin correspondents of Swiss newspapers as saying now the German Air Force will go out for every building in Britain, which is marked with three stars, in Baedeker.
Note.—Baedeker is a series of guide books of the world, so called after a German publisher of that name who issued them in Coblenz. His son transferred the business to Leipzig in 1872.
Official threat
Berlin radio stated to-day:—“Britain pretends to be very astonished that the German air force has picked on Bath as a target. We cannot believe that the British are really as naive as that.
“To be more explicit, let us quote the following sentences from a statement issued by the Wilhelmstrasse:—
“Britain possesses many old cultural monuments of which she is proud, just as Germany is proud of the old Hanseatic towns of Lubeck and Rostock. Should the British continue their wanton and systematic destruction of our cultural treasures, we shall pay them back in the same coin by attacking similar objectives.”

2-: By the Yorkshire Evening Post (Leeds, Yorkshire, England) of Wednesday 29^th April 1942 [No. 16,077, page 4, column 1]:

NOW YORK

EXETER, Bath twice, Norwich, and now York. The pattern of the German “reprisal” raids emerges, and has indeed been declared in the German propaganda references to Britain’s cultural monuments that compare with those to be found in Lubeck and Rostock. Hitler’s “blow for blow” is evidently to be an attack in turn on places of beauty and historic interest, but with this difference from the raids that we have found it necessary to make: there will be no intention to seek out objects of military importance. The German Air Force know their English Baedeker, says the Berlin spokesman—the exact site of Canterbury Cathedral, of famous mansions and castles—“and our airmen will find and hit them.”

However, it was soon noted that it would be impossible for the Luftwaffe to target the buildings in Britain that were marked with three stars in Baedeker’s guidebooks. The following, for example, is from The Scotsman (Edinburgh, Midlothian, Scotland) of Thursday 30^th April 1942 [No. 30,865, page 5, column 7]:

German officials are quoted as saying:—“Now the Luftwaffe will go out for every building in Britain which is marked with three stars in Baedeker”—a reference to that guide book’s habit of marking buildings of great historical interest and architectural value with stars. The Luftwaffe will have difficulty in finding their objectives, however, for the Baedeker system, which can be verified in the last edition of Baedeker’s “London” of 1911, was invariably to give one star to places specially worth visiting, such as St Paul’s, Kensington Palace, or the Houses of Parliament, and two stars to world-famous monuments like the British Museum and the National Gallery.

The expression Baedeker-three-star bomber nevertheless came to be used, as in the following from the Yorkshire Evening Post (Leeds, Yorkshire, England) of Wednesday 29^th April 1942 [No. 16,077, page 1, column 1]:

Evening Post Reporters
YORK, Wednesday.
Among the historic buildings damaged by Hitler’s “Baedeker Three Star” bombers is one scheduled under the Ancient Monuments Act.

The following are some of the earliest occurrences of the expressions Baedeker blitz, Baedeker raid, Baedeker attack and Baedeker bombing that I have found:

1-: From The Windsor Daily Star (Windsor, Ontario, Canada) of Wednesday 29^th April 1942 [Vol. 48, No. 51, page 1, columns 2 & 3]:

Little People of Britain Gird for ‘Baedeker Blitz’

LONDON, Eng., April 29.—Britain’s small town dwellers tugged the chin straps of their steel helmets tighter today, quietly determined to endure Hitler’s threatened “guide book” blitz.
The German air force already has brought death and injury to the island’s historic spots such as Exeter, Bath, Norwich and York, and the Berlin radio has threatened a bombing of “every British building marked with three stars in Baedeker.”

2-: From the Northern Daily Mail (Hartlepool, County Durham, England) of Thursday 30^th April 1942 [No. 19,953, page 3, column 3]:

A short, sharp raid on Norwich, the second on the city since the “Baedeker” raids on cathedral cities started, killed several people and damaged shopping and residential districts last night.

3-: From the column London Views, published in the Daily Record and Mail (Glasgow, Lanarkshire, Scotland) of Thursday 30^th April 1942 [No. 29,725, page 2, column 4]:

NOBODY will deplore the Nazi “Baedeker” attack on York more than the new Archbishop of Canterbury.
I recently talked with the Archbishop about the vulnerability of this historic city to an attack. He fervently hoped that its apparent immunity would continue, not, as he was careful to explain, for personal considerations but because of the enshrined history of its ancient fabric.

4-: From the Evening Chronicle (Newcastle-upon-Tyne, Northumberland, England) of Thursday 30^th April 1942 [No. 20,591, page 2, column 1]:

Vandal Bombing

THERE is something essentially sinister about the avowed policy of “Baedeker bombing” now ventilated by the Luftwaffe, and the immediate answer is not to indulge in competitive vandalism.
We believe the British Government has no such policy, having other tasks to perform. We do not doubt that German buildings of some moment are sometimes hit by British bombs, and that will continue to be the case as the attack sharpens. But we know, and the Germans know, that when our Air Minister says that our task is to cripple the German war machine we speak the truth.
If the Nazis have chosen to equip war factories in old-world German cities (whose culture owes nothing to Nazism) they know what to expect. Hitler is credited with the intention of aiming a crippling blow at his Russian foes this summer, and Britain’s present role is to see that his supply of deadly munitions for that task is made smaller and smaller.
There are old townships in Germany corresponding to Bath, Exeter and York and no attack has been made upon them, neither need we search any guidebooks to find where they are, for they are known to thousands of tourists who visit Germany.
Rather have we sought to bring up-to-date our knowledge of the location of the new German war plants, and when our programme is complete not one of them will be safe.
The war is now entering its most deadly phase and we must be prepared for the foulest fomrs [sic] of attack. The very foundations of civilisation may be imperilled ere the foul thing in our midst is exorcised.