‘No member of this House’, proclaimed Bulstrode Whitelocke in February 1642 ‘ought to publish any speech or passage of this House, though it be very frequent.’ Very frequent it was; by this stage of the Long Parliament more than 100 purported speeches of named members were in printed circulation. Orations attributed to 45 M.P.s had been published, at a time when only ‘75 M.P.s made the motions, spoke to the issues, and delivered the reports of conferences and committees’. Printed speeches must have become a familiar genre to the customers of London booksellers. Invariably they were quarto in format; typically a pamphlet consisted of a single address, between three and eight sides in length and carelessly printed. Titles were informative and unpretentious: Mr. Thomas Pury his Speech upon the clause, the which concerns Deans and Chapters is a representative example. Most gave the date, or alleged date, of delivery, and the name of the printer responsible. There was nothing surreptitious, in other words, about the phenomenon. The chronological Thomason catalogue shows that speeches were significantly more numerous than any other kind of ephemeral tract, at least until March 1642, and that during the first session they were the only source of printed information about parliamentary debates. After March 1642 the flow of publication dried up. Large-scale publication of individual parliamentary speeches is therefore unique to a particular fifteen month period. Their importance, as historical sources, hardly needs stressing. The purpose of this article is primarily to explain the nature, and limitations, of the evidence this material can provide.