Pillar to Post is a book of drawings and text by Osbert Lancaster. It was first published in 1938 and covers the history of western architecture from Ancient Egypt to buildings of the 1930s. There were 40 chapters in the original edition. Lancaster later added two more. Each chapter consists of a page of text on the left and a drawing on the right. The texts vary in length but are typically between 300 and 400 words each.

A second edition was published in 1956 with some additional material, and most of the text and drawings were republished in 1959 in Here, of All Places which combined Pillar to Post and its 1939 successor, Homes Sweet Homes, which covered the interiors of buildings.

Although the texts and the drawings are entertaining and sometimes comic, the book serves a serious purpose: making readers aware of good – and bad – architecture.

The artist and critic Osbert Lancaster joined the staff of The Architectural Review in 1934. His contributions to the magazine included a series of illustrated satires on planning and architecture, under the collective title Progress at Pelvis Bay. The collected articles were turned into a book, under the same title, published in 1936. In the form of a spoof tourist guide it lampooned greedy and philistine property developers and incompetent and smug local government who between them have gradually spoiled a typical English seaside resort. The book received high praise from reviewers, and the publisher, Jock Murray of the firm John Murray, commissioned another book from Lancaster.

The new book, Pillar to Post took its title from an old English term signifying being harassed and dashing about. The book's sub-title is "The Pocket-Lamp of Architecture". It consists of Lancaster's drawings of imaginary exteriors on the odd-numbered pages opposite, on the even ones, short descriptions and critiques of the style. The text is typically between 300 and 400 words for each chapter; the shortest is "Very Early English" – 187 words, depicting a Stonehenge-like structure; the longest is "Scottish Baronial" – 407 words describing a rural Victorian building reminiscent of Balmoral Castle.

Lancaster's biographer James Knox describes Pillar to Post as "a disarming picture-book with a reforming agenda: to address 'the present lamentable state of English architecture' caused by the passivity of the intelligent public who 'when confronted with architecture, whether good, bad or indifferent, remain resolutely dumb – in both the original and transatlantic senses of the word'". Each two-page section of the book has its own title. Some titles are plainly factual, such as "Egypt", "Perpendicular" and "Art Nouveau". Others have more extravagant headings such as "Pont Street Dutch", "Stockbrokers Tudor" and "By-pass Variegated"; although Lancaster said that some of the more whimsical terms were already in circulation, most were either invented or popularised by him. The architectural scholar Christopher Hussey remarked on the author's inventive coinage of terms, and described the book as both perceptive and shrewd. On the reverse of the title page Lancaster wrote, "All the architecture in this book is completely imaginary, and no reference is intended to any actual building, living or dead".

The original 40 sections are:

For the second edition of the book, published by Murray in 1956, Lancaster added two new sections on more recent architectural styles: "Festival Flats" and "The Wide Open Plan".